LSE Logo MBoC Logo

A Highlights from MBoC Selection

Promiscuity of the catalytic Sec7 domain within the guanine nucleotide exchange factor GBF1 in ARF activation, Golgi homeostasis, and effector recruitment

Published Online:https://doi.org/10.1091/mbc.E18-11-0711

Abstract

The integrity of the Golgi and trans-Golgi network (TGN) is disrupted by brefeldin A (BFA), which inhibits the Golgi-localized BFA-sensitive factor (GBF1) and brefeldin A–inhibited guanine nucleotide-exchange factors (BIG1 and BIG2). Using a cellular replacement assay to assess GBF1 functionality without interference from the BIGs, we show that GBF1 alone maintains Golgi architecture; facilitates secretion; activates ADP-ribosylation factor (ARF)1, 3, 4, and 5; and recruits ARF effectors to Golgi membranes. Unexpectedly, GBF1 also supports TGN integrity and recruits numerous TGN-localized ARF effectors. The impact of the catalytic Sec7 domain (Sec7d) on GBF1 functionality was assessed by swapping it with the Sec7d from ARF nucleotide-binding site opener (ARNO)/cytohesin-2, a plasma membrane GEF reported to activate all ARFs. The resulting chimera (GBF1-ARNO-GBF1 [GARG]) targets like GBF1, supports Golgi/TGN architecture, and facilitates secretion. However, unlike GBF1, GARG activates all ARFs (including ARF6) at the Golgi/TGN and recruits additional ARF effectors to the Golgi/TGN. Our results have general implications: 1) GEF’s targeting is independent of Sec7d, but Sec7d influence the GEF substrate specificity and downstream effector events; 2) all ARFs have access to all membranes, but are restricted in their distribution by the localization of their activating GEFs; and 3) effector association with membranes requires the coincidental presence of activated ARFs and specific membrane identifiers.

INTRODUCTION

Compartment integrity and vesicular traffic require the recruitment of numerous proteins from the cytosol to restricted membrane sites to facilitate cargo sorting, vesicle formation, microtubule-based motility, and lipid metabolism (van Vliet et al., 2003). Many such proteins are recruited to membranes by binding to activated forms of small GTPases of the ADP-ribosylation factor (ARF) superfamily. In primate cells, the five ARFs belonging to class I (ARF1 and ARF3), class II (ARF4 and ARF5), and class III (ARF6) localize to different compartments and appear to perform different functions (Hosaka et al., 1996). ARF1 localizes to and presumably functions at multiple compartments, including ERGIC, Golgi, trans-Golgi network (TGN), endosomes, and plasma membrane (Hosaka et al., 1996). ARF3 appears more restricted and is concentrated at the TGN (Padilla et al., 2004; Shin et al., 2004). ARF 4 and ARF5 preferentially localize at the ERGIC and the Golgi, but ARF4 also has been reported to function at the endosome (Volpicelli-Daley et al., 2005; Chun et al., 2008; Duijsings et al., 2009). ARF6 is the most restricted in distribution and localizes and functions predominantly at the plasma membrane (and perhaps to some degree within endosomal compartments) (Cavenagh et al., 1996; Cohen et al., 2007). However, how the specific distribution of the different ARFs is achieved and how the different ARFs inform the recruitment of distinct effectors at each site remain unclear.

Like all GTPases, ARFs function by cycling between an inactive guanosine diphosphate (GDP)-bound state and an active guanosine triphosphate (GTP)-bound form. ARF activation is mediated by a family of guanine nucleotide exchange factors (GEFs) characterized by a conserved catalytic Sec7d, which governs the displacement of GDP from the ARF and thus promotes the binding of the activating GTP. GEFs can be subdivided into the Golgi-localized Brefeldin A (BFA)-sensitive factor (GBF1); BFA-inhibited guanine nucleotide-­exchange factors (BIG1 and BIG2) and the BFA-resistant cytohesins, BRAGs, EFA6; and F-box proteins (Bui et al., 2009; Wright et al., 2014). ARF activation is essential for compartmental integrity and vesicular traffic at the endoplasmic reticulum (ER)–Golgi interface, within the Golgi, and from the TGN to the plasma membrane and requires BFA-sensitive GEFs, as treatment of cells with BFA causes Golgi/TGN collapse and blocks secretion (Oda et al., 1990; Orci et al., 1991).

The relative contributions of the three BFA-sensitive GEFs to the maintenance of intracellular compartments remain unclear. GBF1 appears to be the only GEF acting within the early secretory pathway since GBF1 is the only GEF localizing to the ERGIC and early Golgi (the BIGs localize to the TGN and endosomal compartments), and depleting GBF1 by small interfering RNA (siRNA) or inhibiting it with selective drugs such as Golgicide A (GCA) or LG186 that do not inhibit the BIGs cause the collapse of the Golgi and block secretion (Mansour et al., 1998; Claude et al., 1999; Kawamoto et al., 2002; Garcia-Mata et al., 2003; Szul et al., 2007; Saenz et al., 2009; Boal et al., 2010). GBF1 depletion or inhibition blocks the membrane recruitment of numerous effectors including the heptameric coat protein complex I (COPI) necessary for the formation of recycling COPI vesicles (Aridor et al., 1995; Griffiths et al., 1995; Lowe and Kreis, 1996, 1998), GMAP210 is required for Golgi integrity and positioning (Infante et al., 1999; Pernet-Gallay et al., 2002; Rios et al., 2004), golgin-160 is necessary for the Golgi transit of select cargo (Hicks et al., 2006; Williams et al., 2006), and Golgi-associated four-phosphate adaptor protein 2 (FAPP2) is crucial for sphingolipids transfer and metabolism (Godi et al., 2004; D’Angelo et al., 2007). Despite its preferential concentration at the cis-Golgi, GBF1 is also detected at the TGN, and the extent to which GBF1 acts at the TGN remains largely unknown (Lowery et al., 2013).

BIG1 predominantly localizes to the TGN, but relocates to the nucleus under certain cellular stresses such as serum starvation (Padilla et al., 2004). How BIG1 functions in the nucleus and whether that function is mediated through its nucleotide exchange on ARFs are unknown. BIG1 also appears to perform some function(s) at the medial-Golgi since depletion of BIG1 causes an impairment in the glycosylation of some (ICAM-1 and β-integrin) but not all (E-cadherin) cargo proteins at a step prior to the activity of α1–6 N-acetyl-glucosaminyl-transferase V, an enzyme localized to the trans-Golgi (Shen et al., 2007). In addition, the Golgi membranes in BIG1 siRNA-treated cells appear less compact and sharply defined, with more vesicles present around the abnormal Golgi/TGN than in mock siRNA-treated cells and partial Golgi fragmentation (Boal and Stephens, 2010). In contrast, other reports indicate that depleting BIG1 has no effect on Golgi architecture (as defined by the characteristic localization of giantin and normal COPI distribution [Shen et al., 2006]) or the TGN (as defined by normal localization of golgin-245 [Ishizaki et al., 2008]). Thus, the exact functions of BIG1-mediated ARF activation remain unclear. It also remains unclear whether the lack of strong phenotypes after BIG1 depletion reflect the ability of the related BIG2 to support such functions. The level of functional overlap is difficult to tease out, but BIG1 also performs functions distinct from those of BIG2, as Schwann cell-specific deletion of BIG1 impaired myelination in mice (Miyamoto et al., 2018), showcasing the inability of other GEFs to complement the BIG1 deficit.

BIG2 localizes to the TGN where it colocalizes extensively with BIG1 and also to endosomal compartments (Pacheco-Rodriguez et al., 2002; Shin et al., 2004). BIG2-mediated ARF activation appears essential for the recruitment of the AP1 adaptor protein, since: 1) overexpression of BIG2 in cells where other GEFs are inactivated with BFA maintained AP1 (but not COPI) recruitment to membranes; 2) overexpression of the dominant inactive BIG2/E738K caused the dissociation of AP1 (and Golgi-localized gamma-adaptin ear homology domain ARF-binding protein [GGA1]), but did not affect membrane recruitment of COPI (Shinotsuka et al., 2002a,b); and 3) depletion of BIG2 caused AP1 dissociation (Ishizaki et al., 2008). In addition to AP1, BIG2 also seems to regulate membrane recruitment of GGA3 and golgin-97 since high level expression of the inactive BIG2/E738K results in their dissociation (Shin et al., 2004, 2005). However, conflicting results from Ishizaki et al. (2008) suggest that BIG2 doesn’t regulate GGA3 and golgin-245 recruitment since both remained membrane-associated in cells from which BIG1/2 were depleted individually or together (Ishizaki et al., 2008). Instead, BIG2 may function at the Golgi since the expression of the inactive BIG2/E738K caused the arrest of E-cadherin traffic in the Golgi (Shen et al., 2007, 2012). Thus, although BIG2 involvement in AP1 recruitment is confirmed, the exact role BIG2 plays in the recruitment of other effectors at the TGN remains uncertain. Equally unclear is the functional overlap between BIG2 and BIG1, even though BIG2 regulates at least some specific functions since mutations in BIG2 cause periventricular heterotopia with microcephaly (Sheen et al., 2004), whereas deletion of BIG2 in mice is embryonic lethal (Grzmil et al., 2010), indicating the inability of other GEFs to compensate for the lack of functional BIG2. In addition to their roles at the TGN, both BIG1 and BIG2 localize to recycling endosomes and function to regulate the endosomal cycling of the transferrin receptor (Shen et al., 2006), furin, and TGN46 (Ishizaki et al., 2008). BIGs appear essential for the integrity of the recycling endosomes, as inactivation of BIG1/2 with BFA causes the tubulation of Rab11-positive endosomes (Shin et al., 2004).

Although we increased our understanding of GEF functions through RNA interference (RNAi)-mediated or genetic depletion, drug-mediated inhibition, and expression of dominant inactive forms of GEFs, such approaches have limitations. First, they do not assess whether a particular GEF is sufficient to support a certain event, only that it is required. Second, they do not test whether a GEF supports multiple events, since the inhibition of the first step will by default preclude the analysis of subsequent steps. Here, we utilize a cellular replacement assay to explore the activity of one of the BFA-sensitive GEFs, GBF1, by inhibiting all endogenous GEFs with BFA and then putting back only GBF1 made BFA-resistant by the A795E mutation (GBF1/795).

The Sec7d in GEFs is believed to define its selectivity for ARF substrates, and thereby impact the recruitment of specific effectors by the activated ARFs. To determine how the Sec7d can alter GEF function, we substituted the Sec7d of GBF1 with that of ARF nucleotide-binding site opener (ARNO)/cytohesin-2, a GEF localized to the plasma membrane (Macia et al., 2001; Cohen et al., 2007). The resulting chimera (GARG: GBF1-ARNO-GBF1) was then used in the cellular replacement assay to assess its behavior.

RESULTS

GBF1/795 supports Golgi architecture and recruits ARF effectors to the Golgi

Golgi biogenesis and maintenance and the integrity of the secretory pathway require GBF1-mediated ARFs activation, as shown by Golgi disruption and block in secretion in cells depleted of GBF1 (Kawamoto et al., 2002; Zhao et al., 2002; Garcia-Mata and Sztul, 2003), or in which the catalytic activity of GBF1 is inhibited by BFA (Saenz et al., 2009; Boal et al., 2010). BFA intercalates into an interface formed by the Sec7d of GBF1 and ARF-GDP and prevents GDP expulsion by the catalytic glutamic acid at position 794 within the Sec7d (Beraud-Dufour et al., 1998; Goldberg, 1998; Renault et al., 2003). However, introducing the A795E substitution immediately adjacent to the glutamic acid (to generate GBF1/795) prevents BFA entry into the binding pocket and makes GBF1/795 resistant to BFA. Cells expressing GBF1/795 and treated with BFA maintain Golgi architecture and support secretion (Pocognoni et al., 2018). In agreement, we show that cells expressing GBF1/795 have morphologically recognizable Golgi (labeled with the GM130 Golgi marker), whereas untransfected cells show dispersed Golgi (Figure 1A). The ability of GBF1/795 to activate ARF in the presence of BFA was assessed by monitoring the recruitment of known ARF effectors to the ERGIC/Golgi. We show that GBF1/795 sustains the recruitment of 1) the β-COP component of the heptameric COPI coat that facilitates COPI vesicle formation at the ERGIC and the Golgi (Presley et al., 2002; Elsner et al., 2003; Faini et al., 2012) (Figure 1B); 2) the GMAP210 coiled–coil golgin with a role in maintaining Golgi ribbon integrity and position and containing an ARF1-binding GRAB (grip-related Arf-binding domain that aids its localization to the cis-Golgi (Infante et al., 1999; Pernet-Gallay et al., 2002; Rios et al., 2004) (Figure 1C); 3) the golgin-160 required for the transport of the β1-adrenergic receptor and the GLUT4 glucose transporter through the Golgi (Hicks et al., 2006; Williams et al., 2006) and which localizes to cis- and medial-Golgi (Hicks and Machamer, 2002) (Figure 1D); and 4) the FAPP2 sphingolipid transfer protein essential for proper lipid transport and metabolism that preferentially localizes to cis-Golgi (D’Angelo et al., 2007) (Figure 1E).

FIGURE 1:

FIGURE 1: GBF1/795 supports Golgi architecture and recruits ARF effectors to the Golgi. HeLa cells were transfected with GFP-tagged GBF1/795 for 24 h, treated with BFA (0.5 μg/ml) for 30 min, and processed for IF with antibodies to GFP and the indicated markers. GBF1/795-expressing cells, but not untransfected cells contain morphologically recognizable Golgi and recruit ARF effectors to the Golgi.

GBF1/795 supports TGN integrity and recruits ARF effectors to the TGN

That GBF1/795 supports Golgi homeostasis was expected since GBF1 localizes to the Golgi and functions therein (Zhao et al., 2002, 2006; Garcia-Mata et al., 2003). However, GBF1 is also detected at more distal TGN compartments (Lowery et al., 2013), raising the possibility that GBF1 may impact the biogenesis and/or maintenance of the TGN. Three golgins, golgin-245, golgin-97, and GCC88 (Lu and Hong, 2003; Luke et al., 2003; Yoshino et al., 2003; Derby et al., 2004) that localize to distinct subdomains of the TGN, were used to monitor the ability of GBF1/795 to sustain TGN architecture in BFA-treated cells. Morphologically recognizable TGN structures containing golgin-245 (Figure 2A), golgin-97 (Figure 2B), or GCC88 (Figure 2C) were observed in cells expressing GBF1/795 but not in untransfected cell. Thus, GBF1/795 can support the architecture of at least the TGN subdomains defined by golgin-245, golgin-97, and GCC88 in cells in which the TGN-­localized BIG1 and BIG2 are inactivated with BFA.

FIGURE 2:

FIGURE 2: GBF1/795 maintains TGN architecture and recruits ARF effectors to the TGN. HeLa cells were transfected with GFP-tagged GBF1/795 for 24 h, treated with BFA (0.5 μg/ml) for 30 min, and processed for IF with antibodies to GFP and the indicated markers. GBF1/795-expressing cells, but not untransfected cells, contain morphologically recognizable TGN and recruit ARF effectors to the TGN.

We have shown previously that BIG1 and BIG2 are ARF effectors since they preferentially bind the active GTP-bound forms of ARF4 and ARF5 to localize to the TGN (Lowery et al., 2013). To assess whether BIG1 and BIG2 recruitment to TGN membranes is mediated by GBF1, we examined BIG1 and BIG2 localization in cells expressing GBF1/795 and treated with BFA. Both, BIG1 (Figure 2D) and BIG2 (Figure 2E) were recruited to morphologically recognizable TGN in cells expressing GBF1/795, but not in untransfected cells. BIG1 and BIG2 in untransfected cells showed a fine punctate distribution, suggesting that BIG1/2 may remain membrane bound in the presence of BFA, as would be expected since BFA stabilizes the membrane-associated complex of GEFs with their ARF-GDP substrates (Robineau et al., 2000; Mossessova et al., 2003; Niu et al., 2005; Szul et al., 2005).

ARF activation at the TGN is required for the recruitment of the AP1 and the three GGA1-3 adaptors involved in cargo sorting and delivery from the TGN to compartments of the endosomal system, but it remains unclear which GEF(s) are involved (Robinson, 2004, 2015; Hirst et al., 2012). In addition, the MINT3 adaptor involved in the sorting and trafficking of the furin protease (Han et al., 2008) and the Alzheimer’s precursor protein (APP) (Shrivastava-­Ranjan et al., 2008; Caster and Kahn, 2013) between the TGN and endosomes also is recruited by activated ARF, but the GEF that activates the relevant ARFs is unknown. We show that BFA-treated cells expressing GBF1/795 have dispersed AP1 (Figure 3A), GGA2 (Figure 3B), and GGA3 (Figure 3C), but membrane-localized MINT3 (Figure 3D). To ensure that the lack of TGN staining is not due to technical issues, we show that using the same experimental protocol, we can detect the TGN-localized AP1, GGA2, and GGA3 in cells not treated with BFA (Figure 3, E–G). Thus, GBF1/795-­mediated ARF activation supports the architecture of at least some TGN subcompartments and mediates the membrane recruitment of some (MINT3), but not all (AP-1, GGA2, GGA3), TGN-localized ARF effectors.

FIGURE 3:

FIGURE 3: GBF1/795 shows selectivity for ARF effector recruitment. HeLa cells were transfected with GFP-tagged GBF1/795 for 24 h, treated with BFA (0.5 μg/ml) for 30 min (A–D) or left untreated (E–G), and processed for IF with antibodies to GFP and the indicated markers. BFA-treated GBF1/795-expressing cells, but not untransfected cells, contain morphologically recognizable Golgi/TGN that recruit MINT3, but do not recruit AP1, GGA2, or GGA3 adaptors (A–D). Cells not treated with BFA contain TGN-localized AP1, GGA2, and GGA3 irrespective of expressing GBF1/795 (E–G).

GARG (GBF1 containing Sec7d from ARNO/cytohesin-2) supports Golgi architecture and recruits ARF effectors to the Golgi

The role of the catalytic Sec7 domain in influencing the functional output of GBF1 was assessed by substituting the Sec7d of GBF1 with the Sec7d from ARNO (also called cytohesin-2) to generate the GBF1-ARNO-GBF1 chimera called GARG (Figure 4A). ARNO localizes to the plasma membrane where it regulates actin dynamics and endosomal traffic by activating ARF1 and possibly ARF6 (Frank et al., 1998a,b; Santy et al., 2001). ARNO is not known to activate ARF3 or class II ARFs in vivo. ARNO is intrinsically BFA resistant due to an amino acid sequence in its Sec7d. Since GARG contains a BFA-resistant Sec7d, it is BFA resistant and its cellular functions can be tested without interference from endogenous GBF1/BIG1/BIG2 in cells treated with BFA.

FIGURE 4:

FIGURE 4: Schematic of GARG. (A) Domain organization of GBF1, ARNO, and GARG. The A795E mutation within the Sec7d that confers BFA resistance to GBF1/795 is marked. (B–G) HeLa cells were transfected with Flag-tagged wild-type ARNO (B–D) or GFP-tagged wild-type GBF1 (E–G) for 24 h, treated with BFA (0.5 μg/ml) for 30 min, and processed for IF with antibodies to Flag (B–D) or GFP (E–G) and the indicated markers. Neither ARNO nor wild-type GBF1 maintain Golgi/TGN architecture or recruit ARF effectors to the TGN in BFA-treated cells.

We first tested whether overexpressing ARNO can support Golgi/TGN homeostasis in cells treated with BFA. Cells expressing ARNO do not maintain the Golgi or the TGN, as shown by the dispersed distribution of GM130 (Figure 4B), golgin-97 (Figure 4C), and golgin-245 (Figure 4D). A similar pattern of disruption is observed in cells expressing the BFA-sensitive wild-type GBF1 (Figure 4, E–G). Thus, neither the BFA-resistant ARNO nor the BFA-sensitive wild-type GBF1 can maintain Golgi/TGN in cells treated with BFA.

We then assessed whether GARG can support Golgi/TGN homeostasis. When expressed in HeLa cells, GARG colocalizes with the GM130 Golgi marker, but doesn’t target to the plasma membrane (Figure 5A), indicating targeting analogous to that of GBF1, but not ARNO. This implies that the targeting of GARG to the Golgi is governed by domains within the protein other than the changed Sec7d. GARG is fully functional in sustaining Golgi architecture in cells treated with BFA, as indicated by the characteristic localization of the GM130 Golgi marker in GARG expressing cells but not in untransfected cells (Figure 5B). GARG appears to function in a manner analogous to that of GBF1/795 since it supports the recruitment of the ARF effectors β-COP (Figure 5C; in these panels, cells expressing GARG are identified by the intact pattern of GM130), GMAP210 (Figure 5D), golgin-160 (Figure 5E), and FAPP2 (Figure 5F).

FIGURE 5:

FIGURE 5: GARG supports Golgi architecture and recruits ARF effectors to the Golgi. (A, B) HeLa cells were transfected with GFP-tagged GARG for 24 h and either left untreated (A) or treated with BFA (0.5 μg/ml) for 30 min (B), and processed for IF with antibodies to GFP and GM130. GARG targets to the Golgi in untreated cells (A), and maintains Golgi integrity in BFA-treated cells (B). (C–F) HeLa cells were transfected with Myc-tagged GARG for 24 h, treated with BFA (0.5 μg/ml) for 30 min, and then processed for IF with antibodies to GM130 (to detect cells with intact Golgi, i.e., those expressing GARG) and the indicated markers. Cells containing intact Golgi (i.e., expressing GARG) recruit ARF effectors to the Golgi.

GARG (GBF1 containing Sec7d from ARNO) supports TGN architecture and recruits ARF effectors to the TGN

Because GBF1/795 supports the architecture of the TGN and recruits ARF effectors to the TGN, we examined whether GARG can mediate analogous ARF activation. In these studies, cells expressing GARG are identified by their content of a morphologically recognizable Golgi labeled with the GM130 Golgi marker. We show that BFA-treated cells containing Golgi-localized GM130 (i.e., expressing GARG) have TGN-localized golgin-245 (Figure 6A), golgin-97 (Figure 6B), and GCC88 (Figure 6C), whereas untransfected cells show dispersed patterns for these proteins. Like GBF1/795, GARG facilitates the recruitment of the ARF effectors BIG1 (Figure 6D) and BIG2 (Figure 6E) to the TGN in BFA-treated cells. This suggests that GARG activates ARF4 and ARF5 at the TGN since those ARFs have been shown to be necessary for BIG1/2 membrane association (Lowery et al., 2013). Examination of additional TGN-localized ARF effectors indicates that like GBF1/795, GARG does not support the recruitment of AP1 (Figure 7A) or GGA3 (Figure 7C), but does support the recruitment of GGA2 (Figure 7B) and MINT3 (Figure 7D). Thus, GARG appears to support the recruitment of GGA2 to membranes, a function not performed by GBF1/795.

FIGURE 6:

FIGURE 6: GARG supports TGN integrity and recruits ARF effectors to the TGN. HeLa cells were transfected with Myc-tagged GARG for 24 h, treated with BFA (0.5 μg/ml) for 30 min, and then processed for IF with antibodies to GM130 (to detect cells with intact Golgi, i.e., those expressing GARG) and the indicated markers. Cells containing morphologically recognizable Golgi (i.e., expressing GARG) recruit ARF effectors to the TGN.

FIGURE 7:

FIGURE 7: GARG shows selectivity for ARF effector recruitment. HeLa cells were transfected with GFP-tagged GARG for 24 h, treated with BFA (0.5 μg/ml) for 30 min and processed for IF with antibodies to GFP and the indicated markers. BFA-treated GARG-expressing cells, but not untransfected cells, contain morphologically recognizable Golgi/TGN that recruit GGA2 and MINT3, but do not recruit AP1 or GGA2 adaptors.

GBF1 and GARG support secretion

GBF1-mediated ARF activation is required for protein secretion and cells treated with BFA or the GBF1-specific Golgicide A (GCA), or depleted of GBF1 do not support cargo release (Szul et al., 2007; Saenz et al., 2009). To explore whether GBF1/795 and GARG are sufficient to sustain secretion, we utilized a Gaussia luciferase-based secretion assay and compared secretion from cells transfected with GBF1/795, GARG, or an empty vector in the presence of increasing concentrations of BFA. As shown in Figure 8, cells expressing an empty vector are impaired in secretion, with less than 30% secretion at the lowest BFA concentration and less than 10% at the highest. In contrast, cells expressing GBF1/795 support robust secretion, with more than 75% secretion even at the highest BFA concentration used. Similarly, cells expressing GARG support secretion with an efficiency similar to that of GBF1/795, indicating that GARG can perform all the ARF activation events normally performed by GBF1 within the secretory pathway.

FIGURE 8:

FIGURE 8: GBF1/795 and GARG support protein secretion. HeLa cells were cotransfected with plasmids encoding Gaussia luciferase and GBF1/795, GARG, or empty vector for 24 h, the medium was removed, and the cells were incubated in fresh medium supplemented with the indicated amount of BFA. After a 4-h incubation, the amount of secreted luciferase was measured. GBF1/795 and GARG support secretion in the presence of BFA, whereas cells transfected with empty vector are inhibited.

GBF1 activates a subset of ARFs at the Golgi/TGN

Four of the five human ARFs (ARF1, 3, 4, and 5) localize to the ERGIC/Golgi/TGN and could be activated by GBF1, BIG1, and/or BIG2. To identify the ARFs activated by GBF1, we cotransfected cells with GBF1/795 and each of the five human ARFs; treated cells with BFA to inactivate the endogenous GBF1, BIG1, and BIG2; and monitored the membrane-recruitment of the ARFs as a measure of activation status. Cells coexpressing GBF1/795 and a specific ARF were identified by the presence of the ARF and the presence of intact GM130-labeled Golgi (we routinely observe more than 90% cotransfection with these plasmids). We observed ARF1 (Figure 9A), ARF3 (Figure 9B), ARF4 (Figure 9C), and ARF5 (Figure 9D) in morphologically recognizable Golgi/TGN structures in transfected cells. ARF4 (Figure 9C, arrows) and ARF5 (Figure 9D, arrows) were also present in peripheral punctate structures. In contrast, ARF6 was detected only on the plasma membrane (in agreement with being recruited there by BFA-resistant GEFs [Macia et al., 2001]) and was not recruited to the Golgi/TGN. Thus, the Golgi/TGN-localized GBF1/795 appears to activate ARF1, 3, 4, and 5, but not ARF6.

FIGURE 9:

FIGURE 9: GBF1/795 recruits class I and class II ARFs to the Golgi/TGN. HeLa cells were cotransfected with Myc-tagged GBF1/795 and V5-tagged ARFs for 24 h, treated with BFA (0.5 μg/ml) for 30 min, and then processed for IF with antibodies to GM130 (to detect cells with intact Golgi, i.e., those expressing GBF1/795) and V5. All ARFs except ARF6 are recruited to perinuclear morphologically recognizable Golgi/TGN. ARF4 and ARF5 are also detected on more peripheral elements (arrows).

GARG (GBF1 containing Sec7d from ARNO) activates all ARFs, including ARF6 at the Golgi/TGN

GARG supports all tested functions performed by GBF1/795, implying that GARG activates all the ARFs normally activated by GBF1/795. In agreement, in BFA-treated cells expressing GARG (identified by an intact GM130-labeled Golgi), we detected ARF1 (Figure 10A), ARF3 (Figure 10B), ARF4 (Figure 10C), and ARF5 (Figure 10D) associated with Golgi/TGN membranes. GARG contains the Sec7d from ARNO, which is known to activate ARF6, raising the question of whether GARG could also activate ARF6 on Golgi/TGN membranes. We show that in BFA-treated cells expressing GARG, ARF6 is recruited to the Golgi/TGN, in addition to its normal plasma membrane localization (Figure 10E). Thus, unlike GBF1/795, the Golgi/TGN-localized GARG can recruit ARF6 to Golgi/TGN membranes.

Figure 10:

Figure 10: GARG recruits all ARFs to the Golgi/TGN. HeLa cells were cotransfected with Myc-tagged GARG and V5-tagged ARFs for 24 h, treated with BFA (0.5 μg/ml) for 30 min, and then processed for IF with antibodies to GM130 (to detect cells with intact Golgi, i.e., those expressing GARG) and V5. All ARFs, including ARF6, are recruited to perinuclear morphologically recognizable Golgi/TGN.

GARG does not recruit ARF6 effectors to the Golgi/TGN

GARG activates ARF6 at the Golgi/TGN, raising the possibility that the activated ARF6 can facilitate the recruitment of ARF6 effectors to the Golgi/TGN. We first examined the AP2 adaptor protein component of clathrin-coated pits and vesicles (McMahon and Boucrot, 2011; Mettlen et al., 2018). In both untransfected cells and GARG-­expressing cells, AP2 was detected in a punctate pattern consistent with its usual PM localization without recruitment to the Golgi/TGN-localized GARG (Figure 11A). Similar punctate distribution and lack of Golgi/TGN recruitment was observed for JIP3, ARF6 effector regulating the dynamics of endosomal tubules and impacting neurite morphogenesis of cortical neurons (Suzuki et al., 2010; Montagnac et al., 2011; Marchesin et al., 2015).

Figure 11:

Figure 11: GARG does not recruit ARF6 effectors to the Golgi/TGN. (A–C, E–G) HeLa cells were transfected with Venus-tagged GARG (A–C) or GFP-tagged GBF1/795 (E–G) for 24 h, treated with BFA (0.5 μg/ml) for 30 min, and then processed for IF with antibodies to GFP and either indicated markers or stained with phalloidin. Cells expressing GARG or GBF1/795 do not show Golgi/TGN-localized AP-2, JIP3 or actin. (D, H) HeLa cells were cotransfected with Myc-tagged ARNO and either Venus-tagged GARG (D) or GFP-tagged GBF1/795 (H) for 24 h, treated with BFA (0.5 μg/ml) for 30 min, and then processed for IF with antibodies to Flag and GFP. Cells expressing GARG or GBF1/795 do not show Golgi-localized ARNO. ARNO expression causes partial Golgi/TGN disruption.

Activated ARF6 is known to stimulate PLD to increase the production of PIP2 and the subsequent recruitment of actin (Schafer et al., 2000; Santy and Casanova, 2001; Li, Shome et al., 2003; Hiroyama and Exton, 2005). Examination of actin architecture in GARG-expressing cells shows stress fibers and a subcortical pattern that appears analogous to that in untransfected cells, without preferential recruitment of actin to the Golgi/TGN (Figure 11C). We also examined the behavior of the ARF6 effector ARNO (Santy and Casanova, 2001; Cohen et al., 2007) by cotransfecting GARG and ARNO into cells and assessing ARNO recruitment to the Golgi/TGN. We show that ARNO localizes to the PM, but is not recruited to GARG-containing structures (Figure 11D). ARNO expression has been shown to cause Golgi disruption (Monier et al., 1998) and we also observe a less compacted Golgi in ARNO-expressing cells. Together, our results suggest that GARG-mediated recruitment of ARF6 to the Golgi/TGN does not automatically result in the recruitment of ARF6 effectors (at least the ones tested here) to the Golgi/TGN. An analogous lack of ARF6 effector recruitment is seen in cells expressing the GBF1/795 construct (Figure 11, E–H).

DISCUSSION

Activated ARFs recruit essential cytosolic effectors to the membranes of the ERGIC/Golgi/TGN to facilitate cargo selection and vesicle biogenesis. BFA disrupts this process by inhibiting the catalytic activity of GBF1, BIG1, and BIG2. The specificity of these GEFs in activating one or more ARF in a spatially restricted manner to facilitate recruitment of specific effectors remains poorly defined. To tease apart the functionality of the three GEFs, we used a cell replacement assay in which we inhibit the endogenous GBF1/BIG1/2 with BFA and then put back only GBF1/795 that is insensitive to BFA to probe GBF1 functions without the interference from BIG1/2.

GBF1 functions at the Golgi and the TGN

GBF1 is concentrated at ERGIC and cis-Golgi and functions therein (Zhao et al., 2002; Garcia-Mata et al., 2003). GBF1 is also detected at the TGN, but whether GBF1 controls TGN integrity and the recruitment of ARF effectors at the TGN is less clear since BIG1 and BIG2 have been localized to the TGN (Zhao et al., 2002) and are assumed to act there. Here, we dissected GBF1 cellular function away from BIG1/2 activities.

As expected, GBF1/795 supports Golgi morphology and recruits ARF effectors to the Golgi, including the heptameric COPI coat essential for Golgi homeostasis (Styers et al., 2008); GMAP210, a golgin required for Golgi integrity and positioning relative to the MTOC (Rios et al., 2004; Cardenas et al., 2009); golgin-160, a transport factor required for the trafficking of select transmembrane cargos through the Golgi (Hicks et al., 2006; Williams et al., 2006); and the FAPP2, a sphingolipid transfer protein required for Golgi to PM transport (Godi et al., 2004; Tuuf and Mattjus, 2014). GBF/795 alone supports the secretion of soluble proteins, indicating that it is the sole BFA-sensitive GEF required for this process.

Unexpectedly, GBF1/795 also supports the architecture of TGN. The TGN is a complex organelle composed of multiple subdomains containing distinct marker proteins (reviewed in Kjer-Nielsen et al., 1999; Luke et al., 2003; Derby et al., 2004, 2007; Gleeson et al., 2004; Spang, 2016). For example, golgin-245 and golgin-97 localize to a distinct domain than the GCC88 and GCC185 golgins, as shown by the amplification of distinct, nonoverlapping golgin-­positive structures in cells simultaneously expressing GCC88 and golgin-97 (Derby et al., 2004). We show that cells expressing GBF1/795 contain TGN-localized golgin-245, golgin-97, and GCC88 while they are dispersed in untransfected cells treated with BFA. Thus, at least some subdomains of the TGN are maintained by GBF1/795 without the participation of the BIGs.

Additional evidence for GBF1 function at the TGN was shown by the recruitment of BIG1 and BIG2 (effectors of ARF4 and ARF5; Lowery et al., 2013) and of MINT3, an effector of an as yet uncharacterized ARF (Shrivastava-Ranjan et al., 2008; Caster and Kahn, 2013). In contrast, GBF1/795 did not support the recruitment of AP1, GGA2, and GGA3, suggesting that this function is normally performed by other GEFs, perhaps BIG1/2. The lack of AP1 recruitment by GBF1 is consistent with previous studies implicating BIG1/2 in AP1 recruitment (Ishizaki et al., 2008). The regulation of GGA1 and GGA3 recruitment is unclear: whereas overexpression of the inactive BIG2/E738K causes GGA1 (Shinotsuka et al., 2002a) and GGA3 (Shin et al., 2005) to dissociate from membranes, those findings contradict other studies showing that the depletion of BIG2 has no visible impact on GGA3 membrane association (Ishizaki et al., 2008). To further complicate matters, GGA1-3 have been shown to bind GBF1 (Lefrancois and McCormick, 2007), raising the possibility that GBF1 might mediate the ARF activation that recruits GGAs to the TGN. In support: 1) GGA3 was recruited to membranes in BFA-treated MDCK cells in which only GBF1 (but not BIG1/2) is BFA resistant due to an altered Sec7d sequence in the canine GBF1 (Lefrancois and McCormick, 2007); 2) RNAi-mediated GBF1 depletion caused GGA3 dissociation from membranes (Boal and Stephens, 2010); and 3) the expression of the dominant, inactive GBF1/E794K caused the dissociation of all three GGA1-3 from membranes (Lefrancois and McCormick, 2007). However, a contradictory result showing that selectively inactivating only GBF1 with GCA maintains GGA3 on the membranes (Boal et al., 2010) underscores the difficulty in assigning a role to a particular GEF at the TGN. Our definitive results confirm that GBF1 alone is unable to support GGA2 or GGA3 recruitment. Thus, it appears that all three GGAs are recruited to the TGN through ARFs activated by the BIGs.

Together, our results suggest that GBF1 functions at multiple compartments of the secretory pathway to support the recruitment of distinct ARF effectors to the ERGIC (i.e., GMAP-210), the Golgi (i.e., golgin-160) and the TGN (i.e., MINT3). The spatially differential recruitment of effectors implies that factors in addition to the GEF and the ARF activated by that GEF govern effector localization and thereby control the downstream events.

GBF1 is promiscuous and activates all class I and class II, but not class III, ARFs

Four of the five human ARFs (ARF1, 3, 4, and 5) localize to the Golgi/TGN, with ARF4 and ARF5 also associating with the ERGIC (Cavenagh et al., 1996; Hosaka et al., 1996; Lowe et al., 1996). All are activated by BFA-sensitive GEFs since all four quickly redistribute from the membranes in BFA-treated cells, albeit some ARF4/5 dissociates more slowly from ERGIC membranes (Chun et al., 2008). The single class III ARF6 predominantly localizes to the plasma membrane and is activated by BFA-insensitive GEFs, as it remains membrane-bound in BFA-treated cells (Cavenagh et al., 1996; Aikawa and Martin, 2005; Cohen et al., 2007).

The ARF specificities of the three BFA-sensitive GEFs remain poorly defined. For example, analyses of GBF1 show that 1) recombinant GBF1 activates ARF5, but doesn’t activate ARF1 or ARF3 (Claude et al., 1999); 2) endogenous GBF1 coprecipitates with ARF1 and ARF4, but not with ARF3 in BFA-treated cells in which GBF1 is predicted to be trapped in a complex with its substrates (Szul et al., 2007); 3) GBF1 cycling time on the membrane is altered by ARF1-GDP, indicating that it functions as a substrate (Niu et al., 2005; Szul et al., 2005); and 4) the removal of ARF1 and ARF4 (but no other single or double ARFs) causes Golgi tubulation analogous to that resulting from GBF1 depletion (Volpicelli-Daley et al., 2005). The conclusion most consistent with these findings suggests that GBF1 activates ARF1 and 4, but perhaps not the other ARFs.

BIG1 purified from bovine brain shows activity toward ARF1 and ARF3 (Morinaga et al., 1996), whereas analyses of BIG2 provide contradictory results and show that 1) recombinant BIG2 catalyzes guanine–nucleotide exchange on ARF1 and ARF5 in vitro (Togawa et al., 1999); 2) overexpression of BIG2 in cells causes an increase in activated ARF1 and ARF3 (Shin et al., 2005); and 3) only the removal of the ARF1 and ARF3 pair alters transferrin cycling, a function regulated by BIG2 (Volpicelli-Daley et al., 2005). The most consistent findings suggest that BIG1 and BIG2 both activate ARF1 and 3, but probably not the other ARFs.

Using BFA-treated cells expressing GBF1/795, we show that GBF1/795 recruits ARF1, 3, 4, and 5 to the Golgi. ARF 1/4/5 are predicted to be activated by GBF1 based on their localization to the ERGIC/cis-Golgi. Unexpectedly, GBF1/795 also recruited ARF3, previously assumed to be activated by the BIGs at the TGN. Thus, the catalytic Sec7d of GBF1 can utilize all human class I and class II ARFs as substrates. In contrast, ARF6 was not recruited to the Golgi in cells expressing GBF1/795, indicating that the Sec7d of GBF1 discriminates against the single class III ARF.

GARG supports all functions of GBF1/795, but also performs additional functions

It is unknown to what degree the Sec7d of a GEF influences the behavior of that GEF. We explored this for GBF1 by swapping its Sec7d with the Sec7d from ARNO/cytohesin-2, a GEF localized at the plasma membrane where it regulates actin dynamics and endosomal traffic by activating ARF1 and possibly ARF6 (Frank et al., 1998a,b; Caumont et al., 2000; Turner and Brown, 2001). The resulting GARG chimera localizes in a manner analogous to endogenous GBF1, indicating that targeting of GBF1 is independent of its Sec7d. The Sec7d might be the only domain within GBF1 not involved in its localization, since GBF1 association with membranes has been shown to require an intact N-terminus (Monetta et al., 2007), HDS1 (Meissner et al., 2018; Quilty et al., 2018), HDS2 (Pocognoni et al., 2018), as well as the C-terminus (Garcia-Mata and Sztul, 2003). GARG does not target to the plasma membrane, the localization of endogenous ARNO/cytohesin-2, indicating that the Sec7d has limited input into GEF targeting and that GEF’s selectivity for membranes is governed through interactions other than with their substrate ARFs. It seems that the catalytic Sec7d functions autonomously and in fact is a mere “worker” positioned at select sites through interactions defined by the rest of GBF1. It is likely that this is a general paradigm for GEFs.

We assessed whether GARG can perform the functions supported by GBF1/795. We show that like GBF1/795, GARG supports Golgi and TGN integrity, facilitates secretion of cargo, and mediates the recruitment of all the Golgi/TGN-localized ARF effectors that GBF1/795 recruits. Unexpectedly, GARG also supports the recruitment of GGA2, a function that GBF1/795 does not perform. This suggests that GARG activates an ARF in addition to those activated by GBF1/795, and that it is this additional ARF that recruits GGA2 (see below).

GBF1 containing the Sec7d of ARNO/cytohesin-2 activates all ARFs, including ARF6 at the Golgi/TGN

The substrate specificity of ARNO/cytohesin-2 is unclear. Purified ARNO/cytohesin-2 has the highest activity on ARF1, 80% less activity on ARF5, and 95% less activity on ARF6 (Frank et al., 1998b; Macia et al., 2001; Zeeh et al., 2006). A more recent study shows that purified ARNO/cytohesin-2 artificially tethered to lipid membranes has the highest specific activity on ARF4 and ARF5, lower and equivalent activity on ARF1 and ARF3, and lowest activity on ARF6 (Peurois et al., 2017). In vivo studies show that ARNO/cytohesin-2 activates ARF1 in cells, but whether it activates other ARFs was not explored in those works (Cohen et al., 2007).

Our finding that GARG can support all processes supported by GBF1/795 suggested that GARG activates all the ARFs that GBF1/795 activates. In agreement, we show that GARG recruits ARF1, ARF3, ARF4, and ARF5 to the Golgi/TGN, a finding consistent with the ability of purified ARNO to activate these ARFs. Furthermore, GARG also recruits ARF6 at the Golgi/TGN, a process not supported by GBF1/795 but consistent with the ability of the ARNO Sec7d to activate ARF6.

These results have a number of implications: 1) the ability of the Golgi/TGN-­localized GARG to activate ARF3, ARF4 and ARF5 suggests that the Sec7d within the endogenous ARNO/cytohesin-2 localized to the plasma membrane can activate the same ARFs. Yet ARF3, ARF4 and ARF5 are not found on the plasma membrane, indicating that the presence of a GEF is insufficient to define the distribution of activated ARFs. 2) The ability of GARG to activate ARF6 indicates that the Sec7d controls the ARF selectivity of the GEF since the Sec7d from ARNO enabled the “mostly GBF1” GARG to activate ARF6. This also implies that the selectivity of the Sec7d impacts the recruitment of effectors and controls the downstream signaling events. 3) The ability of GARG to recruit all ARFs including ARF6 to Golgi/TGN indicates that all ARFs, including ARF6, have access to all cellular membranes. ARF6 has been assumed to be always membrane bound, based on findings showing that the ARF6/T27N mutant (assumed to represent the GDP-bound form) is found on membrane structures resembling endosomes and is recovered exclusively in the membrane fraction after fractionation of transfected cells (Peters et al., 1995; Radhakrishna et al., 1996; D’Souza-Schorey et al., 1998). However, more recent studies reported that the ARF6/T27N mutant is prone to aggregation (Macia et al., 2004). This group generated the ARF6/T44N mutant (based on the GDP-GTP structural cycle of ARF6 [Menetrey et al., 2000; Pasqualato et al., 2001]) and showed that the ARF6/T44N and wild-type ARF6 are recovered in the membrane and the cytosolic fractions of transfected cells. These findings suggest that endogenous ARF6 in the GDP-bound state may cycle between membranes and the cytosol and thereby have access to all cellular membranes. This implies that the selective subcellular distribution of ARFs is informed by their activation through spatially restricted GEFs but is incompletely governed by it (see point 1 above). 4) Although GARG recruited all ARFs to the Golgi/TGN, not all ARF effectors were recruited to Golgi/TGN. Specifically, AP1 and GGA3 were not recruited, implying that effectors associate with membranes not just by the virtue of activated ARFs but also require specific membrane identifiers.

MATERIALS AND METHODS

Antibodies

Polyclonal anti-GFP (ab290), mouse monoclonal anti-β COP (ab6323), and rabbit monoclonal FAPP2 (ab235300) antibody were purchased from Abcam (Cambridge, MA). Monoclonal anti-GBF1 (612116), GGA2 (BD612612), GGA3 (BD612310), GM130 (BD610823), GMAP210 (611713), golgin-245 (BD611280), and polyclonal anti-MINT3 (BD611380) were obtained from BD Bioscience (San Jose, CA). Polyclonal MINT3 antibodies were also a gift from Richard Kahn (Emory University, Atlanta, GA). Monoclonal anti-V5 (R960-25), golgin-97(A21270), polyclonal anti-GM130 (PA1-077), and anti-JIP3 (PA5-59728) were purchased from Thermo Scientific (Rockford, IL). Monoclonal anti-GFP (A11120), anti-BIG1 (MABS1247) raised against 311 amino acid fragment (residues 212–522) of human BIG1, anti-BIG2 (MABS1246) against 249 amino acids from the N-terminal region of human BIG2, anti-AP1 (A4200), and polyclonal anti-Flag (F7425) and anti-golgin-160 (HPA040044) were from MilliporeSigma (Burlington, MA). Polyclonal anti-GCC88 (GTX120148) were from GeneTex (Irvine, CA). Secondary goat anti-rabbit antibodies conjugated with Alexa 488 (A11034) or Alexa 594 (A11012), goat anti-mouse conjugated with Alexa 488 (A11029) or Alexa 594 (A11042), and phalloidin conjugated with Alexa 594 (A12381) were from Thermo Scientific (Hanover Park, IL).

Plasmids

GBF1/795 has been described previously (Pocognoni et al., 2018). Replacement of GBF1 Sec7d with Sec7d from ARNO/cytohesin-2 in full-length GBF1 was performed in multiple PCRs, including three overlapping PCRs. Primers used were 5′-gaccaagctgtgagatagtagatgg-3′ (GBF1-F) and 5′-ccatgttgaaatctggcaggagacagg-3′ (GBF1/ARNO-R) to amplify N-terminus of GBF1, before GBF1 Sec7; 5′-cctgccagatttcaacatggacccca-3′ (ARNO/GBF1-F) and 5′-gttctcccggtcattcccgtcatcc-3′ (ARNO/GBF1-R) to amplify ARNO Sec7; 5′-cgggaatgaccgggagaactatgtgtg-3′ (GBF1/ARNO-F), and 5′-cacgatgaaggacagcgattcc-3′ (GBF1-R) to amplify C-terminus of GBF1, after GBF1 Sec7. The GBF1 sequence was amplified from wild-type GBF1 sequence in pcDNA4-myc/his vector (Invitrogen), and the Sec7d was amplified from FLAG-tagged ARNO/cytohesin-2 that was a gift from James Casanova (University of Virginia, Charlottesville, VA). The used primers had incorporated restriction sites for cloning the GARG chimera into the pcDNA4 vector. V5-tagged ARF constructs were a gift from Richard Kahn (Emory University, Atlanta, GA).

Mammalian cell culture and transfection

HeLa cells were grown in MEM supplemented with glucose and glutamine and 10% fetal bovine serum, 100 U/ml penicillin, 100 mg/ml streptomycin, and 1 mM sodium pyruvate; all of these reagents were purchased from Cellgro (Manassas, VA). Cells were grown at 37°C in 5% CO2 until ∼75% confluent and were transfected with Mirus TransIT-LT1 transfection reagent (Mirus Bio Corp., Madison, WI), according to the manufacturer’s instructions. After transfection, cells were grown overnight and used for experiments.

Immunofluorescence microscopy

In some experiments, cells were incubated with 5 μg/ml BFA for 30 min before processing by immunofluorescence. Cells were processed for immunofluorescence as follows: cells were washed three times in phosphate-buffered saline (PBS), fixed in 3% paraformaldehyde in PBS for 10 min, and quenched with 10 mM ammonium chloride in PBS for another 10 min. Subsequently, cells were permeabilized in 0.1% Triton X-100 in PBS for 7 min. The coverslips were then washed in PBS, blocked in PBS containing 2.5% goat serum and 0.2% Tween 20 for 5 min, and in PBS, 0.4% fish skin gelatin and 0.2% Tween-20 for another 5 min. Cells were incubated with primary antibody diluted in 0.4% fish skin gelatin for 1 h at room temperature, washed in PBS–0.2% Tween 20, and blocked as described above. Then, cells were incubated with secondary antibodies diluted in 2.5% goat serum for 45 min at room temperature. Nuclei were stained using Hoechst, and coverslips were washed with PBS–0.2% Tween 20 and mounted on slides in ProLong Gold antifade reagent (Invitrogen, Madison WI). Cells were visualized with a Leitz Wetlzar microscope with epifluorescence and Hoffman Modulation Contrast optics from Chroma Technology. Images were captured with a 12-bit CCD camera from Q imaging using iVision-Mac software.

Confocal microscopy

Confocal imaging was with a PerkinElmer Ultraview ERS 6FE spinning disk confocal attached to a Nikon TE 2000-U microscope equipped with laser and filter sets for FITC, TRITC, and DAPI fluorescence. Images were captured using a Hamamatsu C9100-50 EM-CCD camera (Hamamatsu Photonics K.K., Hamamatsu City, Japan) and 60× or 100× Plan APO oil-immersion objectives. The imaging system was controlled by Volocity 6.2 software (PerkinElmer, Shelton, CT).

Secretion assay

HeLa cells were cotransfected in 96-well plates with plasmids encoding Gaussia luciferase (GLuc) and the GBF1/795 or GARG construct (1:9 mass ratio). An empty vector was used as a negative control. The next day, the medium was removed, and the cells were washed to remove secreted luciferase and incubated in 25 μl of fresh medium supplemented with the indicated amount of BFA. After 4 h of incubation, the medium was transferred into another 96-well plate, and the amount of secreted luciferase was measured with BioLux Gaussia Luciferase Assay Kit (New England BioLabs) according to the manufacturer’s recommendations.

FOOTNOTES

This article was published online ahead of print in MBoC in Press (http://www.molbiolcell.org/cgi/doi/10.1091/mbc.E18-11-0711) on April 3, 2019.

Abbreviations used:
AP1

adaptor protein 1

APP

Alzheimer’s precursor protein

ARF

ADP-ribosylation factor

ARNO

ARF nucleotide-binding site opener

BFA

Brefeldin A

BIG1 and BIG2

BFA-inhibited guanine nucleotide-exchange factors

COPI

coat protein complex I

FAPP2

Golgi-associated four-phosphate adaptor protein 2

GARG

GBF1-ARNO-GBF1

GBF1

Golgi-­localized BFA-­sensitive factor

GCA

Golgicide A

GDP

guanosine diphosphate

GEF

guanine nucleotide exchange factor

GGA

Golgi-localized gamma-adaptin ear homology domain ARF-binding protein

GLuc

Gaussia luciferase

GTP

guanosine triphosphate

PBS

phosphate-buffered saline

TGN

trans-Golgi network.

ACKNOWLEDGMENTS

We regret the many omissions of citations of outstanding work in the field that could not be cited or discussed in greater detail due to space limitations. This work was supported by grants from the National Institutes of Health (R01GM122802 to E.S., R01AI125561 to G.A.B. and E.S., and R01DK110292 to S.R.) and the National Science Foundation (MCB-1615607 to E.S.).

REFERENCES

  • Aikawa Y, Martin TF (2005). ADP-ribosylation factor 6 regulation of phosphatidylinositol-4,5-bisphosphate synthesis, endocytosis, and exocytosis. Methods Enzymol 404, 422–431. Crossref, MedlineGoogle Scholar
  • Aridor M, Bannykh SI, Rowe T, Balch WE (1995). Sequential coupling between COPII and COPI vesicle coats in endoplasmic reticulum to Golgi transport. J Cell Biol 131, 875–893. Crossref, MedlineGoogle Scholar
  • Beraud-Dufour S, Robineau S, Chardin P, Paris S, Chabre M, Cherfils J, Antonny B (1998). A glutamic finger in the guanine nucleotide exchange factor ARNO displaces Mg2+ and the beta-phosphate to destabilize GDP on ARF1. Embo J 17, 3651–3659. Crossref, MedlineGoogle Scholar
  • Boal F, Guetzoyan L, Sessions RB, Zeghouf M, Spooner RA, Lord JM, Cherfils J, Clarkson GJ, Roberts LM, Stephens DJ (2010). LG186: An inhibitor of GBF1 function that causes Golgi disassembly in human and canine cells. Traffic 11, 1537–1551. Crossref, MedlineGoogle Scholar
  • Boal F, Stephens DJ (2010). Specific functions of BIG1 and BIG2 in endomembrane organization. PLoS One 5, e9898. Crossref, MedlineGoogle Scholar
  • Bui QT, Golinelli-Cohen MP, Jackson CL (2009). Large Arf1 guanine nucleotide exchange factors: evolution, domain structure, and roles in membrane trafficking and human disease. Mol Genet Genomics 282, 329–350. Crossref, MedlineGoogle Scholar
  • Cardenas J, Rivero S, Goud B, Bornens M, Rios RM (2009). Golgi localisation of GMAP210 requires two distinct cis-membrane binding mechanisms. BMC Biol 7, 56. Crossref, MedlineGoogle Scholar
  • Caster AH, Kahn RA (2013). Recruitment of the Mint3 adaptor is necessary for export of the amyloid precursor protein (APP) from the Golgi complex. J Biol Chem 288, 28567–28580. Crossref, MedlineGoogle Scholar
  • Caumont AS, Vitale N, Gensse M, Galas MC, Casanova JE, Bader MF (2000). Identification of a plasma membrane-associated guanine nucleotide exchange factor for ARF6 in chromaffin cells. Possible role in the regulated exocytotic pathway. J Biol Chem 275, 15637–15644. Crossref, MedlineGoogle Scholar
  • Cavenagh MM, Whitney JA, Carroll K, Zhang C, Boman AL, Rosenwald AG, Mellman I, Kahn RA (1996). Intracellular distribution of Arf proteins in mammalian cells. Arf6 is uniquely localized to the plasma membrane. J Biol Chem 271, 21767–21774. Crossref, MedlineGoogle Scholar
  • Chun J, Shapovalova Z, Dejgaard SY, Presley JF, Melancon P (2008). Characterization of class I and II ADP-ribosylation factors (Arfs) in live cells: GDP-bound class II Arfs associate with the ER-Golgi intermediate compartment independently of GBF1. Mol Biol Cell 19, 3488–3500. LinkGoogle Scholar
  • Claude A, Zhao BP, Kuziemsky CE, Dahan S, Berger SJ, Yan JP, Armold AD, Sullivan EM, Melancon P (1999). GBF1: A novel Golgi-associated BFA-resistant guanine nucleotide exchange factor that displays specificity for ADP-ribosylation factor 5. J Cell Biol 146, 71–84. Crossref, MedlineGoogle Scholar
  • Cohen LA, Honda A, Varnai P, Brown FD, Balla T, Donaldson JG (2007). Active Arf6 recruits ARNO/cytohesin GEFs to the PM by binding their PH domains. Mol Biol Cell 18, 2244–2253. LinkGoogle Scholar
  • D’Angelo G, Polishchuk E, Di Tullio G, Santoro M, Di Campli A, Godi A, West G, Bielawski J, Chuang CC, van der Spoel AC, et al. (2007). Glycosphingolipid synthesis requires FAPP2 transfer of glucosylceramide. Nature 449, 62–67. Crossref, MedlineGoogle Scholar
  • D’Souza-Schorey C, van Donselaar E, Hsu VW, Yang C, Stahl PD, Peters PJ (1998). ARF6 targets recycling vesicles to the plasma membrane: insights from an ultrastructural investigation. J Cell Biol 140, 603–616. Crossref, MedlineGoogle Scholar
  • Derby MC, Lieu ZZ, Brown D, Stow JL, Goud B, Gleeson PA (2007). The trans-Golgi network Golgin, GCC185, is required for endosome-to-Golgi transport and maintenance of Golgi structure. Traffic 8, 758–773. Crossref, MedlineGoogle Scholar
  • Derby MC, van Vliet C, Brown D, Luke MR, Lu L, Hong W, Stow JL, Gleeson PA (2004). Mammalian GRIP domain proteins differ in their membrane binding properties and are recruited to distinct domains of the TGN. J Cell Sci 117(Pt 24), 5865–5874. Crossref, MedlineGoogle Scholar
  • Duijsings D, Lanke KH, van Dooren SH, van Dommelen MM, Wetzels R, de Mattia F, Wessels E, van Kuppeveld FJ (2009). Differential membrane association properties and regulation of class I and class II Arfs. Traffic 10, 316–323. Crossref, MedlineGoogle Scholar
  • Elsner M, Hashimoto H, Simpson JC, Cassel D, Nilsson T, Weiss M (2003). Spatiotemporal dynamics of the COPI vesicle machinery. EMBO Rep 4, 1000–1004. Crossref, MedlineGoogle Scholar
  • Faini M, Prinz S, Beck R, Schorb M, Riches JD, Bacia K, Brugger B, Wieland FT, Briggs JA (2012). The structures of COPI-coated vesicles reveal alternate coatomer conformations and interactions. Science 336, 1451–1454. Crossref, MedlineGoogle Scholar
  • Frank SR, Hatfield JC, Casanova JE (1998a). Remodeling of the actin cytoskeleton is coordinately regulated by protein kinase C and the ADP-ribosylation factor nucleotide exchange factor ARNO. Mol Biol Cell 9, 3133–3146. LinkGoogle Scholar
  • Frank S, Upender S, Hansen SH, Casanova JE (1998b). ARNO is a guanine nucleotide exchange factor for ADP-ribosylation factor 6. J Biol Chem 273, 23–27. Crossref, MedlineGoogle Scholar
  • Garcia-Mata R, Sztul E (2003). The membrane-tethering protein p115 interacts with GBF1, an ARF guanine-nucleotide-exchange factor. EMBO Rep 4, 320–325. Crossref, MedlineGoogle Scholar
  • Garcia-Mata R, Szul T, Alvarez C, Sztul E (2003). ADP-ribosylation factor/COPI-dependent events at the endoplasmic reticulum-Golgi interface are regulated by the guanine nucleotide exchange factor GBF1. Mol Biol Cell 14, 2250–2261. LinkGoogle Scholar
  • Gleeson PA, Lock JG, Luke MR, Stow JL (2004). Domains of the TGN: coats, tethers and G proteins. Traffic 5, 315–326. Crossref, MedlineGoogle Scholar
  • Godi A, Di Campli A, Konstantakopoulos A, Di Tullio G, Alessi DR, Kular GS, Daniele T, Marra P, Lucocq JM, De Matteis MA (2004). FAPPs control Golgi-to-cell-surface membrane traffic by binding to ARF and PtdIns(4)P. Nat Cell Biol 6, 393–404. Crossref, MedlineGoogle Scholar
  • Goldberg J (1998). Structural basis for activation of ARF GTPase: mechanisms of guanine nucleotide exchange and GTP-myristoyl switching. Cell 95, 237–248. Crossref, MedlineGoogle Scholar
  • Griffiths G, Pepperkok R, Locker JK, Kreis TE (1995). Immunocytochemical localization of beta-COP to the ER-Golgi boundary and the TGN. J Cell Sci 108(Pt 8), 2839–2856. MedlineGoogle Scholar
  • Grzmil P, Enkhbaatar Z, Gundsambuu B, Oidovsambuu O, Yalcin S, Wolf S, Engel W, Neesen J (2010). Early embryonic lethality in gene trap mice with disruption of the Arfgef2 gene. Int J Dev Biol 54, 1259–1266. Crossref, MedlineGoogle Scholar
  • Han J, Wang Y, Wang S, Chi C (2008). Interaction of Mint3 with Furin regulates the localization of Furin in the trans-Golgi network. J Cell Sci 121(Pt 13), 2217–2223. Crossref, MedlineGoogle Scholar
  • Hicks SW, Horn TA, McCaffery JM, Zuckerman DM, Machamer CE (2006). Golgin-160 promotes cell surface expression of the beta-1 adrenergic receptor. Traffic 7, 1666–1677. Crossref, MedlineGoogle Scholar
  • Hicks SW, Machamer CE (2002). The NH2-terminal domain of Golgin-160 contains both Golgi and nuclear targeting information. J Biol Chem 277, 35833–35839. Crossref, MedlineGoogle Scholar
  • Hiroyama M, Exton JH (2005). Localization and regulation of phospholipase D2 by ARF6. J Cell Biochem 95, 149–164. Crossref, MedlineGoogle Scholar
  • Hirst J, Borner GH, Antrobus R, Peden AA, Hodson NA, Sahlender DA, Robinson MS (2012). Distinct and overlapping roles for AP-1 and GGAs revealed by the knocksideways system. Curr Biol 22, 1711–1716. Crossref, MedlineGoogle Scholar
  • Hosaka M, Toda K, Takatsu H, Torii S, Murakami K, Nakayama K (1996). Structure and intracellular localization of mouse ADP-ribosylation factors type 1 to type 6 (ARF1-ARF6). J Biochem (Tokyo) 120, 813–819. Crossref, MedlineGoogle Scholar
  • Infante C, Ramos-Morales F, Fedriani C, Bornens M, Rios RM (1999). GMAP-210, A cis-Golgi network-associated protein, is a minus end microtubule-binding protein. J Cell Biol 145, 83–98. Crossref, MedlineGoogle Scholar
  • Ishizaki R, Shin HW, Mitsuhashi H, Nakayama K (2008). Redundant roles of BIG2 and BIG1, guanine-nucleotide exchange factors for ADP-ribosylation factors in membrane traffic between the trans-Golgi network and endosomes. Mol Biol Cell 19, 2650–2660. LinkGoogle Scholar
  • Kawamoto K, Yoshida Y, Tamaki H, Torii S, Shinotsuka C, Yamashina S, Nakayama K (2002). GBF1, a guanine nucleotide exchange factor for ADP-ribosylation factors, is localized to the cis-Golgi and involved in membrane association of the COPI coat. Traffic 3, 483–495. Crossref, MedlineGoogle Scholar
  • Kjer-Nielsen L, van Vliet C, Erlich R, Toh BH, Gleeson PA (1999). The Golgi-targeting sequence of the peripheral membrane protein p230. J Cell Sci 112(Pt 11), 1645–1654. Crossref, MedlineGoogle Scholar
  • Lefrancois S, McCormick PJ (2007). The Arf GEF GBF1 is required for GGA recruitment to Golgi membranes. Traffic 8, 1440–1451. Crossref, MedlineGoogle Scholar
  • Li HS, Shome K, Rojas R, Rizzo MA, Vasudevan C, Fluharty E, Santy LC, Casanova JE, Romero G (2003). The guanine nucleotide exchange factor ARNO mediates the activation of ARF and phospholipase D by insulin. BMC Cell Biol 4, 13. Crossref, MedlineGoogle Scholar
  • Lowe M, Kreis TE (1996). In vivo assembly of coatomer, the COP-I coat precursor. J Biol Chem 271, 30725–30730. Crossref, MedlineGoogle Scholar
  • Lowe M, Kreis TE (1998). Regulation of membrane traffic in animal cells by COPI. Biochim Biophys Acta 1404, 53–66. Crossref, MedlineGoogle Scholar
  • Lowe SL, Wong SH, Hong W (1996). The mammalian ARF-like protein 1 (Arl1) is associated with the Golgi complex. J Cell Sci 109(Pt 1), 209–220. MedlineGoogle Scholar
  • Lowery J, Szul T, Styers M, Holloway Z, Oorschot V, Klumperman J, Sztul E (2013). The Sec7 guanine nucleotide exchange factor GBF1 regulates membrane recruitment of BIG1 and BIG2 guanine nucleotide exchange factors to the trans-Golgi network (TGN). J Biol Chem 288, 11532–11545. Crossref, MedlineGoogle Scholar
  • Lu L, Hong W (2003). Interaction of Arl1-GTP with GRIP domains recruits autoantigens Golgin-97 and Golgin-245/p230 onto the Golgi. Mol Biol Cell 14, 3767–3781. LinkGoogle Scholar
  • Luke MR, Kjer-Nielsen L, Brown DL, Stow JL, Gleeson PA (2003). GRIP domain-mediated targeting of two new coiled-coil proteins, GCC88 and GCC185, to subcompartments of the trans-Golgi network. J Biol Chem 278, 4216–4226. Crossref, MedlineGoogle Scholar
  • Macia E, Chabre M, Franco M (2001). Specificities for the small G proteins ARF1 and ARF6 of the guanine nucleotide exchange factors ARNO and EFA6. J Biol Chem 276, 24925–24930. Crossref, MedlineGoogle Scholar
  • Macia E, Luton F, Partisani M, Cherfils J, Chardin P, Franco M (2004). The GDP-bound form of Arf6 is located at the plasma membrane. J Cell Sci 117(Pt 11), 2389–2398. Crossref, MedlineGoogle Scholar
  • Mansour SJ, Herbrick JA, Scherer SW, Melancon P (1998). Human GBF1 is a ubiquitously expressed gene of the sec7 domain family mapping to 10q24. Genomics 54, 323–327. Crossref, MedlineGoogle Scholar
  • Marchesin V, Castro-Castro A, Lodillinsky C, Castagnino A, Cyrta J, Bonsang-Kitzis H, Fuhrmann L, Irondelle M, Infante E, Montagnac G, et al. (2015). ARF6-JIP3/4 regulate endosomal tubules for MT1-MMP exocytosis in cancer invasion. J Cell Biol 211, 339–358. Crossref, MedlineGoogle Scholar
  • McMahon HT, Boucrot E (2011). Molecular mechanism and physiological functions of clathrin-mediated endocytosis. Nat Rev Mol Cell Biol 12, 517–533. Crossref, MedlineGoogle Scholar
  • Meissner JM, Bhatt JM, Lee E, Styers ML, Ivanova AA, Kahn RA, Sztul E (2018). The ARF guanine nucleotide exchange factor GBF1 is targeted to Golgi membranes through a PIP-binding domain. J Cell Sci 131. Crossref, MedlineGoogle Scholar
  • Menetrey J, Macia E, Pasqualato S, Franco M, Cherfils J (2000). Structure of Arf6-GDP suggests a basis for guanine nucleotide exchange factors specificity. Nat Struct Biol 7, 466–469. Crossref, MedlineGoogle Scholar
  • Mettlen M, Chen PH, Srinivasan S, Danuser G, Schmid SL (2018). Regulation of clathrin-mediated endocytosis. Annu Rev Biochem 87, 871–896. Crossref, MedlineGoogle Scholar
  • Miyamoto Y, Torii T, Tago K, Tanoue A, Takashima S, Yamauchi J (2018). BIG1/Arfgef1 and Arf1 regulate the initiation of myelination by Schwann cells in mice. Sci Adv 4, eaar4471. Crossref, MedlineGoogle Scholar
  • Monetta P, Slavin I, Romero N, Alvarez C (2007). Rab1b Interacts with GBF1, Modulates both ARF1 dynamics and COPI association. Mol Biol Cell 18, 2400–2410. LinkGoogle Scholar
  • Monier S, Chardin P, Robineau S, Goud B (1998). Overexpression of the ARF1 exchange factor ARNO inhibits the early secretory pathway and causes the disassembly of the Golgi complex. J Cell Sci 111(Pt 22), 3427–3436. MedlineGoogle Scholar
  • Montagnac G, de Forges H, Smythe E, Gueudry C, Romao M, Salamero J, Chavrier P (2011). Decoupling of activation and effector binding underlies ARF6 priming of fast endocytic recycling. Curr Biol 21, 574–579. Crossref, MedlineGoogle Scholar
  • Morinaga N, Tsai SC, Moss J, Vaughan M (1996). Isolation of a brefeldin A-inhibited guanine nucleotide-exchange protein for ADP ribosylation factor (ARF) 1 and ARF3 that contains a Sec7-like domain. Proc Natl Acad Sci USA 93, 12856–12860. Crossref, MedlineGoogle Scholar
  • Mossessova E, Corpina RA, Goldberg J (2003). Crystal structure of ARF1*Sec7 complexed with Brefeldin A and its implications for the guanine nucleotide exchange mechanism. Mol Cell 12, 1403–1411. Crossref, MedlineGoogle Scholar
  • Niu TK, Pfeifer AC, Lippincott-Schwartz J, Jackson CL (2005). Dynamics of GBF1, a Brefeldin A-sensitive Arf1 exchange factor at the Golgi. Mol Biol Cell 16, 1213–1222. LinkGoogle Scholar
  • Oda K, Fujiwara T, Ikehara Y (1990). Brefeldin A arrests the intracellular transport of viral envelope proteins in primary cultured rat hepatocytes and HepG2 cells. Biochem J 265, 161–167. Crossref, MedlineGoogle Scholar
  • Orci L, Tagaya M, Amherdt M, Perrelet A, Donaldson JG, Lippincott-Schwartz J, Klausner RD, Rothman JE (1991). Brefeldin A, a drug that blocks secretion, prevents the assembly of non-clathrin-coated buds on Golgi cisternae. Cell 64, 1183–1195. Crossref, MedlineGoogle Scholar
  • Pacheco-Rodriguez G, Moss J, Vaughan M (2002). BIG1 and BIG2: brefeldin A-inhibited guanine nucleotide-exchange proteins for ADP-ribosylation factors. Methods Enzymol 345, 397–404. Crossref, MedlineGoogle Scholar
  • Padilla PI, Pacheco-Rodriguez G, Moss J, Vaughan M (2004). Nuclear localization and molecular partners of BIG1, a brefeldin A-inhibited guanine nucleotide-exchange protein for ADP-ribosylation factors. Proc Natl Acad Sci USA 101, 2752–2757. Crossref, MedlineGoogle Scholar
  • Pasqualato S, Menetrey J, Franco M, Cherfils J (2001). The structural GDP/GTP cycle of human Arf6. EMBO Rep 2, 234–238. Crossref, MedlineGoogle Scholar
  • Pernet-Gallay K, Antony C, Johannes L, Bornens M, Goud B, Rios RM (2002). The overexpression of GMAP-210 blocks anterograde and retrograde transport between the ER and the Golgi apparatus. Traffic 3, 822–832. Crossref, MedlineGoogle Scholar
  • Peters PJ, Hsu VW, Ooi CE, Finazzi D, Teal SB, Oorschot V, Donaldson JG, Klausner RD (1995). Overexpression of wild-type and mutant ARF1 and ARF6: distinct perturbations of nonoverlapping membrane compartments. J Cell Biol 128, 1003–1017. Crossref, MedlineGoogle Scholar
  • Peurois F, Veyron S, Ferrandez Y, Ladid I, Benabdi S, Zeghouf M, Peyroche G, Cherfils J (2017). Characterization of the activation of small GTPases by their GEFs on membranes using artificial membrane tethering. Biochem J 474, 1259–1272. Crossref, MedlineGoogle Scholar
  • Pocognoni CA, Viktorova EG, Wright J, Meissner JM, Sager G, Lee E, Belov GA, Sztul E (2018). Highly conserved motifs within the large Sec7 ARF guanine nucleotide exchange factor GBF1 target it to the Golgi and are critical for GBF1 activity. Am J Physiol Cell Physiol 314, C675–C689. Crossref, MedlineGoogle Scholar
  • Presley JF, Ward TH, Pfeifer AC, Siggia ED, Phair RD, Lippincott-Schwartz J (2002). Dissection of COPI and Arf1 dynamics in vivo and role in Golgi membrane transport. Nature 417, 187–193. Crossref, MedlineGoogle Scholar
  • Quilty D, Chan CJ, Yurkiw K, Bain A, Babolmorad G, Melancon P (2018). The Arf-GDP-regulated recruitment of GBF1 to Golgi membranes requires domains HDS1 and HDS2 and a Golgi-localized protein receptor. J Cell Sci 132. MedlineGoogle Scholar
  • Radhakrishna H, Klausner RD, Donaldson JG (1996). Aluminum fluoride stimulates surface protrusions in cells overexpressing the ARF6 GTPase. J Cell Biol 134, 935–947. Crossref, MedlineGoogle Scholar
  • Renault L, Guibert B, Cherfils J (2003). Structural snapshots of the mechanism and inhibition of a guanine nucleotide exchange factor. Nature 426, 525–530. Crossref, MedlineGoogle Scholar
  • Rios RM, Sanchis A, Tassin AM, Fedriani C, Bornens M (2004). GMAP-210 recruits gamma-tubulin complexes to cis-Golgi membranes and is required for Golgi ribbon formation. Cell 118, 323–335. Crossref, MedlineGoogle Scholar
  • Robineau S, Chabre M, Antonny B (2000). Binding site of brefeldin A at the interface between the small G protein ADP-ribosylation factor 1 (ARF1) and the nucleotide-exchange factor Sec7 domain. Proc Natl Acad Sci USA 97, 9913–9918. Crossref, MedlineGoogle Scholar
  • Robinson MS (2004). Adaptable adaptors for coated vesicles. Trends Cell Biol 14, 167–174. Crossref, MedlineGoogle Scholar
  • Robinson MS (2015). Forty years of clathrin-coated vesicles. Traffic 16, 1210–1238. Crossref, MedlineGoogle Scholar
  • Saenz JB, Sun WJ, Chang JW, Li J, Bursulaya B, Gray NS, Haslam DB (2009). Golgicide A reveals essential roles for GBF1 in Golgi assembly and function. Nat Chem Biol 5, 157–165. Crossref, MedlineGoogle Scholar
  • Santy LC, Casanova JE (2001). Activation of ARF6 by ARNO stimulates epithelial cell migration through downstream activation of both Rac1 and phospholipase D. J Cell Biol 154, 599–610. Crossref, MedlineGoogle Scholar
  • Santy LC, Frank SR, Casanova JE (2001). Expression and analysis of ARNO and ARNO mutants and their effects on ADP-ribosylation factor (ARF)-mediated actin cytoskeletal rearrangements. Methods Enzymol 329, 256–264. Crossref, MedlineGoogle Scholar
  • Schafer DA, D’Souza-Schorey C, Cooper JA (2000). Actin assembly at membranes controlled by ARF6. Traffic 1, 892–903. Crossref, MedlineGoogle Scholar
  • Sheen VL, Ganesh VS, Topcu M, Sebire G, Bodell A, Hill RS, Grant PE, Shugart YY, Imitola J, Khoury SJ, et al. (2004). Mutations in ARFGEF2 implicate vesicle trafficking in neural progenitor proliferation and migration in the human cerebral cortex. Nat Genet 36, 69–76. Crossref, MedlineGoogle Scholar
  • Shen X, Hong MS, Moss J, Vaughan M (2007). BIG1, a brefeldin A-inhibited guanine nucleotide-exchange protein, is required for correct glycosylation and function of integrin beta1. Proc Natl Acad Sci USA 104, 1230–1235. Crossref, MedlineGoogle Scholar
  • Shen X, Li CC, Aponte AM, Shen RF, Billings EM, Moss J, Vaughan M (2012). Brefeldin A-inhibited ADP-ribosylation factor activator BIG2 regulates cell migration via integrin beta1 cycling and actin remodeling. Proc Natl Acad Sci USA 109, 14464–14469. Crossref, MedlineGoogle Scholar
  • Shen X, Xu KF, Fan Q, Pacheco-Rodriguez G, Moss J, Vaughan M (2006). Association of brefeldin A-inhibited guanine nucleotide-exchange protein 2 (BIG2) with recycling endosomes during transferrin uptake. Proc Natl Acad Sci USA 103, 2635–2640. Crossref, MedlineGoogle Scholar
  • Shin HW, Morinaga N, Noda M, Nakayama K (2004). BIG2, a guanine nucleotide exchange factor for ADP-ribosylation factors: its localization to recycling endosomes and implication in the endosome integrity. Mol Biol Cell 15, 5283–5294. LinkGoogle Scholar
  • Shin HW, Shinotsuka C, Nakayama K (2005). Expression of BIG2 and analysis of its function in mammalian cells. Methods Enzymol 404, 206–215. Crossref, MedlineGoogle Scholar
  • Shinotsuka C, Waguri S, Wakasugi M, Uchiyama Y, Nakayama K (2002a). Dominant-negative mutant of BIG2, an ARF-guanine nucleotide exchange factor, specifically affects membrane trafficking from the trans-Golgi network through inhibiting membrane association of AP-1 and GGA coat proteins. Biochem Biophys Res Commun 294, 254–260. Crossref, MedlineGoogle Scholar
  • Shinotsuka C, Yoshida Y, Kawamoto K, Takatsu H, Nakayama K (2002b). Overexpression of an ADP-ribosylation factor-guanine nucleotide exchange factor, BIG2, uncouples brefeldin A-induced adaptor protein-1 coat dissociation and membrane tubulation. J Biol Chem 277, 9468–9473. Crossref, MedlineGoogle Scholar
  • Shrivastava-Ranjan P, Faundez V, Fang G, Rees H, Lah JJ, Levey AI, Kahn RA (2008). Mint3/X11gamma is an ADP-ribosylation factor-dependent adaptor that regulates the traffic of the Alzheimer’s precursor protein from the trans-Golgi network. Mol Biol Cell 19, 51–64. LinkGoogle Scholar
  • Spang A (2016). Membrane tethering complexes in the endosomal system. Front Cell Dev Biol 4, 35. Crossref, MedlineGoogle Scholar
  • Styers ML, O’Connor AK, Grabski R, Cormet-Boyaka E, Sztul E (2008). Depletion of β-COP reveals a role for COP-I in compartmentalization of secretory compartments and in biosynthetic transport of caveolin-1. Am J Physiol Cell Physiol 294, C1485–C1498. Crossref, MedlineGoogle Scholar
  • Suzuki A, Arikawa C, Kuwahara Y, Itoh K, Watanabe M, Watanabe H, Suzuki T, Funakoshi Y, Hasegawa H, Kanaho Y (2010). The scaffold protein JIP3 functions as a downstream effector of the small GTPase ARF6 to regulate neurite morphogenesis of cortical neurons. FEBS Lett 584, 2801–2806. Crossref, MedlineGoogle Scholar
  • Szul T, Garcia-Mata R, Brandon E, Shestopal S, Alvarez C, Sztul E (2005). Dissection of membrane dynamics of the ARF-guanine nucleotide exchange factor GBF1. Traffic 6, 374–385. Crossref, MedlineGoogle Scholar
  • Szul T, Grabski R, Lyons S, Morohashi Y, Shestopal S, Lowe M, Sztul E (2007). Dissecting the role of the ARF guanine nucleotide exchange factor GBF1 in Golgi biogenesis and protein trafficking. J Cell Sci 120(Pt 22), 3929–3940. Crossref, MedlineGoogle Scholar
  • Togawa A, Morinaga N, Ogasawara M, Moss J, Vaughan M (1999). Purification and cloning of a brefeldin A-inhibited guanine nucleotide-exchange protein for ADP-ribosylation factors. J Biol Chem 274, 12308–12315. Crossref, MedlineGoogle Scholar
  • Turner CE, Brown MC (2001). Cell motility: ARNOand ARF6 at the cutting edge. Curr Biol 11, R875–R877. Crossref, MedlineGoogle Scholar
  • Tuuf J, Mattjus P (2014). Membranes and mammalian glycolipid transferring proteins. Chem Phys Lipids 178, 27–37. Crossref, MedlineGoogle Scholar
  • van Vliet C, Thomas EC, Merino-Trigo A, Teasdale RD, Gleeson PA (2003). Intracellular sorting and transport of proteins. Prog Biophys Mol Biol 83, 1–45. Crossref, MedlineGoogle Scholar
  • Volpicelli-Daley LA, Li Y, Zhang CJ, Kahn RA (2005). Isoform-selective effects of the depletion of ADP-ribosylation factors 1–5 on membrane traffic. Mol Biol Cell 16, 4495–4508. LinkGoogle Scholar
  • Williams D, Hicks SW, Machamer CE, Pessin JE (2006). Golgin-160 is required for the Golgi membrane sorting of the insulin-responsive glucose transporter GLUT4 in adipocytes. Mol Biol Cell 17, 5346–5355. LinkGoogle Scholar
  • Wright J, Kahn RA, Sztul E (2014). Regulating the large Sec7 ARF guanine nucleotide exchange factors: the when, where and how of activation. Cell Mol Life Sci 71, 3419–3438. Crossref, MedlineGoogle Scholar
  • Yoshino A, Bieler BM, Harper DC, Cowan DA, Sutterwala S, Gay DM, Cole NB, McCaffery JM, Marks MS (2003). A role for GRIP domain proteins and/or their ligands in structure and function of the trans Golgi network. J Cell Sci 116(Pt 21), 4441–4454. Crossref, MedlineGoogle Scholar
  • Zeeh JC, Zeghouf M, Grauffel C, Guibert B, Martin E, Dejaegere A, Cherfils J (2006). Dual specificity of the interfacial inhibitor brefeldin a for arf proteins and sec7 domains. J Biol Chem 281, 11805–11814. Crossref, MedlineGoogle Scholar
  • Zhao X, Claude A, Chun J, Shields DJ, Presley JF, Melancon P (2006). GBF1, a cis-Golgi and VTCs-localized ARF-GEF, is implicated in ER-to-Golgi protein traffic. J Cell Sci 119(Pt 18), 3743–3753. Crossref, MedlineGoogle Scholar
  • Zhao X, Lasell TK, Melancon P (2002). Localization of large ADP-ribosylation factor-guanine nucleotide exchange factors to different Golgi compartments: evidence for distinct functions in protein traffic. Mol Biol Cell 13, 119–133. LinkGoogle Scholar
  • Aikawa Y, Martin TF (2005). ADP-ribosylation factor 6 regulation of phosphatidylinositol-4,5-bisphosphate synthesis, endocytosis, and exocytosis. Methods Enzymol 404, 422–431. Crossref, MedlineGoogle Scholar
  • Aridor M, Bannykh SI, Rowe T, Balch WE (1995). Sequential coupling between COPII and COPI vesicle coats in endoplasmic reticulum to Golgi transport. J Cell Biol 131, 875–893. Crossref, MedlineGoogle Scholar
  • Beraud-Dufour S, Robineau S, Chardin P, Paris S, Chabre M, Cherfils J, Antonny B (1998). A glutamic finger in the guanine nucleotide exchange factor ARNO displaces Mg2+ and the beta-phosphate to destabilize GDP on ARF1. Embo J 17, 3651–3659. Crossref, MedlineGoogle Scholar
  • Boal F, Guetzoyan L, Sessions RB, Zeghouf M, Spooner RA, Lord JM, Cherfils J, Clarkson GJ, Roberts LM, Stephens DJ (2010). LG186: An inhibitor of GBF1 function that causes Golgi disassembly in human and canine cells. Traffic 11, 1537–1551. Crossref, MedlineGoogle Scholar
  • Boal F, Stephens DJ (2010). Specific functions of BIG1 and BIG2 in endomembrane organization. PLoS One 5, e9898. Crossref, MedlineGoogle Scholar
  • Bui QT, Golinelli-Cohen MP, Jackson CL (2009). Large Arf1 guanine nucleotide exchange factors: evolution, domain structure, and roles in membrane trafficking and human disease. Mol Genet Genomics 282, 329–350. Crossref, MedlineGoogle Scholar
  • Cardenas J, Rivero S, Goud B, Bornens M, Rios RM (2009). Golgi localisation of GMAP210 requires two distinct cis-membrane binding mechanisms. BMC Biol 7, 56. Crossref, MedlineGoogle Scholar
  • Caster AH, Kahn RA (2013). Recruitment of the Mint3 adaptor is necessary for export of the amyloid precursor protein (APP) from the Golgi complex. J Biol Chem 288, 28567–28580. Crossref, MedlineGoogle Scholar
  • Caumont AS, Vitale N, Gensse M, Galas MC, Casanova JE, Bader MF (2000). Identification of a plasma membrane-associated guanine nucleotide exchange factor for ARF6 in chromaffin cells. Possible role in the regulated exocytotic pathway. J Biol Chem 275, 15637–15644. Crossref, MedlineGoogle Scholar
  • Cavenagh MM, Whitney JA, Carroll K, Zhang C, Boman AL, Rosenwald AG, Mellman I, Kahn RA (1996). Intracellular distribution of Arf proteins in mammalian cells. Arf6 is uniquely localized to the plasma membrane. J Biol Chem 271, 21767–21774. Crossref, MedlineGoogle Scholar
  • Chun J, Shapovalova Z, Dejgaard SY, Presley JF, Melancon P (2008). Characterization of class I and II ADP-ribosylation factors (Arfs) in live cells: GDP-bound class II Arfs associate with the ER-Golgi intermediate compartment independently of GBF1. Mol Biol Cell 19, 3488–3500. LinkGoogle Scholar
  • Claude A, Zhao BP, Kuziemsky CE, Dahan S, Berger SJ, Yan JP, Armold AD, Sullivan EM, Melancon P (1999). GBF1: A novel Golgi-associated BFA-resistant guanine nucleotide exchange factor that displays specificity for ADP-ribosylation factor 5. J Cell Biol 146, 71–84. Crossref, MedlineGoogle Scholar
  • Cohen LA, Honda A, Varnai P, Brown FD, Balla T, Donaldson JG (2007). Active Arf6 recruits ARNO/cytohesin GEFs to the PM by binding their PH domains. Mol Biol Cell 18, 2244–2253. LinkGoogle Scholar
  • D’Angelo G, Polishchuk E, Di Tullio G, Santoro M, Di Campli A, Godi A, West G, Bielawski J, Chuang CC, van der Spoel AC, et al. (2007). Glycosphingolipid synthesis requires FAPP2 transfer of glucosylceramide. Nature 449, 62–67. Crossref, MedlineGoogle Scholar
  • D’Souza-Schorey C, van Donselaar E, Hsu VW, Yang C, Stahl PD, Peters PJ (1998). ARF6 targets recycling vesicles to the plasma membrane: insights from an ultrastructural investigation. J Cell Biol 140, 603–616. Crossref, MedlineGoogle Scholar
  • Derby MC, Lieu ZZ, Brown D, Stow JL, Goud B, Gleeson PA (2007). The trans-Golgi network Golgin, GCC185, is required for endosome-to-Golgi transport and maintenance of Golgi structure. Traffic 8, 758–773. Crossref, MedlineGoogle Scholar
  • Derby MC, van Vliet C, Brown D, Luke MR, Lu L, Hong W, Stow JL, Gleeson PA (2004). Mammalian GRIP domain proteins differ in their membrane binding properties and are recruited to distinct domains of the TGN. J Cell Sci 117(Pt 24), 5865–5874. Crossref, MedlineGoogle Scholar
  • Duijsings D, Lanke KH, van Dooren SH, van Dommelen MM, Wetzels R, de Mattia F, Wessels E, van Kuppeveld FJ (2009). Differential membrane association properties and regulation of class I and class II Arfs. Traffic 10, 316–323. Crossref, MedlineGoogle Scholar
  • Elsner M, Hashimoto H, Simpson JC, Cassel D, Nilsson T, Weiss M (2003). Spatiotemporal dynamics of the COPI vesicle machinery. EMBO Rep 4, 1000–1004. Crossref, MedlineGoogle Scholar
  • Faini M, Prinz S, Beck R, Schorb M, Riches JD, Bacia K, Brugger B, Wieland FT, Briggs JA (2012). The structures of COPI-coated vesicles reveal alternate coatomer conformations and interactions. Science 336, 1451–1454. Crossref, MedlineGoogle Scholar
  • Frank SR, Hatfield JC, Casanova JE (1998a). Remodeling of the actin cytoskeleton is coordinately regulated by protein kinase C and the ADP-ribosylation factor nucleotide exchange factor ARNO. Mol Biol Cell 9, 3133–3146. LinkGoogle Scholar
  • Frank S, Upender S, Hansen SH, Casanova JE (1998b). ARNO is a guanine nucleotide exchange factor for ADP-ribosylation factor 6. J Biol Chem 273, 23–27. Crossref, MedlineGoogle Scholar
  • Garcia-Mata R, Sztul E (2003). The membrane-tethering protein p115 interacts with GBF1, an ARF guanine-nucleotide-exchange factor. EMBO Rep 4, 320–325. Crossref, MedlineGoogle Scholar
  • Garcia-Mata R, Szul T, Alvarez C, Sztul E (2003). ADP-ribosylation factor/COPI-dependent events at the endoplasmic reticulum-Golgi interface are regulated by the guanine nucleotide exchange factor GBF1. Mol Biol Cell 14, 2250–2261. LinkGoogle Scholar
  • Gleeson PA, Lock JG, Luke MR, Stow JL (2004). Domains of the TGN: coats, tethers and G proteins. Traffic 5, 315–326. Crossref, MedlineGoogle Scholar
  • Godi A, Di Campli A, Konstantakopoulos A, Di Tullio G, Alessi DR, Kular GS, Daniele T, Marra P, Lucocq JM, De Matteis MA (2004). FAPPs control Golgi-to-cell-surface membrane traffic by binding to ARF and PtdIns(4)P. Nat Cell Biol 6, 393–404. Crossref, MedlineGoogle Scholar
  • Goldberg J (1998). Structural basis for activation of ARF GTPase: mechanisms of guanine nucleotide exchange and GTP-myristoyl switching. Cell 95, 237–248. Crossref, MedlineGoogle Scholar
  • Griffiths G, Pepperkok R, Locker JK, Kreis TE (1995). Immunocytochemical localization of beta-COP to the ER-Golgi boundary and the TGN. J Cell Sci 108(Pt 8), 2839–2856. MedlineGoogle Scholar
  • Grzmil P, Enkhbaatar Z, Gundsambuu B, Oidovsambuu O, Yalcin S, Wolf S, Engel W, Neesen J (2010). Early embryonic lethality in gene trap mice with disruption of the Arfgef2 gene. Int J Dev Biol 54, 1259–1266. Crossref, MedlineGoogle Scholar
  • Han J, Wang Y, Wang S, Chi C (2008). Interaction of Mint3 with Furin regulates the localization of Furin in the trans-Golgi network. J Cell Sci 121(Pt 13), 2217–2223. Crossref, MedlineGoogle Scholar
  • Hicks SW, Horn TA, McCaffery JM, Zuckerman DM, Machamer CE (2006). Golgin-160 promotes cell surface expression of the beta-1 adrenergic receptor. Traffic 7, 1666–1677. Crossref, MedlineGoogle Scholar
  • Hicks SW, Machamer CE (2002). The NH2-terminal domain of Golgin-160 contains both Golgi and nuclear targeting information. J Biol Chem 277, 35833–35839. Crossref, MedlineGoogle Scholar
  • Hiroyama M, Exton JH (2005). Localization and regulation of phospholipase D2 by ARF6. J Cell Biochem 95, 149–164. Crossref, MedlineGoogle Scholar
  • Hirst J, Borner GH, Antrobus R, Peden AA, Hodson NA, Sahlender DA, Robinson MS (2012). Distinct and overlapping roles for AP-1 and GGAs revealed by the knocksideways system. Curr Biol 22, 1711–1716. Crossref, MedlineGoogle Scholar
  • Hosaka M, Toda K, Takatsu H, Torii S, Murakami K, Nakayama K (1996). Structure and intracellular localization of mouse ADP-ribosylation factors type 1 to type 6 (ARF1-ARF6). J Biochem (Tokyo) 120, 813–819. Crossref, MedlineGoogle Scholar
  • Infante C, Ramos-Morales F, Fedriani C, Bornens M, Rios RM (1999). GMAP-210, A cis-Golgi network-associated protein, is a minus end microtubule-binding protein. J Cell Biol 145, 83–98. Crossref, MedlineGoogle Scholar
  • Ishizaki R, Shin HW, Mitsuhashi H, Nakayama K (2008). Redundant roles of BIG2 and BIG1, guanine-nucleotide exchange factors for ADP-ribosylation factors in membrane traffic between the trans-Golgi network and endosomes. Mol Biol Cell 19, 2650–2660. LinkGoogle Scholar
  • Kawamoto K, Yoshida Y, Tamaki H, Torii S, Shinotsuka C, Yamashina S, Nakayama K (2002). GBF1, a guanine nucleotide exchange factor for ADP-ribosylation factors, is localized to the cis-Golgi and involved in membrane association of the COPI coat. Traffic 3, 483–495. Crossref, MedlineGoogle Scholar
  • Kjer-Nielsen L, van Vliet C, Erlich R, Toh BH, Gleeson PA (1999). The Golgi-targeting sequence of the peripheral membrane protein p230. J Cell Sci 112(Pt 11), 1645–1654. Crossref, MedlineGoogle Scholar
  • Lefrancois S, McCormick PJ (2007). The Arf GEF GBF1 is required for GGA recruitment to Golgi membranes. Traffic 8, 1440–1451. Crossref, MedlineGoogle Scholar
  • Li HS, Shome K, Rojas R, Rizzo MA, Vasudevan C, Fluharty E, Santy LC, Casanova JE, Romero G (2003). The guanine nucleotide exchange factor ARNO mediates the activation of ARF and phospholipase D by insulin. BMC Cell Biol 4, 13. Crossref, MedlineGoogle Scholar
  • Lowe M, Kreis TE (1996). In vivo assembly of coatomer, the COP-I coat precursor. J Biol Chem 271, 30725–30730. Crossref, MedlineGoogle Scholar
  • Lowe M, Kreis TE (1998). Regulation of membrane traffic in animal cells by COPI. Biochim Biophys Acta 1404, 53–66. Crossref, MedlineGoogle Scholar
  • Lowe SL, Wong SH, Hong W (1996). The mammalian ARF-like protein 1 (Arl1) is associated with the Golgi complex. J Cell Sci 109(Pt 1), 209–220. MedlineGoogle Scholar
  • Lowery J, Szul T, Styers M, Holloway Z, Oorschot V, Klumperman J, Sztul E (2013). The Sec7 guanine nucleotide exchange factor GBF1 regulates membrane recruitment of BIG1 and BIG2 guanine nucleotide exchange factors to the trans-Golgi network (TGN). J Biol Chem 288, 11532–11545. Crossref, MedlineGoogle Scholar
  • Lu L, Hong W (2003). Interaction of Arl1-GTP with GRIP domains recruits autoantigens Golgin-97 and Golgin-245/p230 onto the Golgi. Mol Biol Cell 14, 3767–3781. LinkGoogle Scholar
  • Luke MR, Kjer-Nielsen L, Brown DL, Stow JL, Gleeson PA (2003). GRIP domain-mediated targeting of two new coiled-coil proteins, GCC88 and GCC185, to subcompartments of the trans-Golgi network. J Biol Chem 278, 4216–4226. Crossref, MedlineGoogle Scholar
  • Macia E, Chabre M, Franco M (2001). Specificities for the small G proteins ARF1 and ARF6 of the guanine nucleotide exchange factors ARNO and EFA6. J Biol Chem 276, 24925–24930. Crossref, MedlineGoogle Scholar
  • Macia E, Luton F, Partisani M, Cherfils J, Chardin P, Franco M (2004). The GDP-bound form of Arf6 is located at the plasma membrane. J Cell Sci 117(Pt 11), 2389–2398. Crossref, MedlineGoogle Scholar
  • Mansour SJ, Herbrick JA, Scherer SW, Melancon P (1998). Human GBF1 is a ubiquitously expressed gene of the sec7 domain family mapping to 10q24. Genomics 54, 323–327. Crossref, MedlineGoogle Scholar
  • Marchesin V, Castro-Castro A, Lodillinsky C, Castagnino A, Cyrta J, Bonsang-Kitzis H, Fuhrmann L, Irondelle M, Infante E, Montagnac G, et al. (2015). ARF6-JIP3/4 regulate endosomal tubules for MT1-MMP exocytosis in cancer invasion. J Cell Biol 211, 339–358. Crossref, MedlineGoogle Scholar
  • McMahon HT, Boucrot E (2011). Molecular mechanism and physiological functions of clathrin-mediated endocytosis. Nat Rev Mol Cell Biol 12, 517–533. Crossref, MedlineGoogle Scholar
  • Meissner JM, Bhatt JM, Lee E, Styers ML, Ivanova AA, Kahn RA, Sztul E (2018). The ARF guanine nucleotide exchange factor GBF1 is targeted to Golgi membranes through a PIP-binding domain. J Cell Sci 131. Crossref, MedlineGoogle Scholar
  • Menetrey J, Macia E, Pasqualato S, Franco M, Cherfils J (2000). Structure of Arf6-GDP suggests a basis for guanine nucleotide exchange factors specificity. Nat Struct Biol 7, 466–469. Crossref, MedlineGoogle Scholar
  • Mettlen M, Chen PH, Srinivasan S, Danuser G, Schmid SL (2018). Regulation of clathrin-mediated endocytosis. Annu Rev Biochem 87, 871–896. Crossref, MedlineGoogle Scholar
  • Miyamoto Y, Torii T, Tago K, Tanoue A, Takashima S, Yamauchi J (2018). BIG1/Arfgef1 and Arf1 regulate the initiation of myelination by Schwann cells in mice. Sci Adv 4, eaar4471. Crossref, MedlineGoogle Scholar
  • Monetta P, Slavin I, Romero N, Alvarez C (2007). Rab1b Interacts with GBF1, Modulates both ARF1 dynamics and COPI association. Mol Biol Cell 18, 2400–2410. LinkGoogle Scholar
  • Monier S, Chardin P, Robineau S, Goud B (1998). Overexpression of the ARF1 exchange factor ARNO inhibits the early secretory pathway and causes the disassembly of the Golgi complex. J Cell Sci 111(Pt 22), 3427–3436. MedlineGoogle Scholar
  • Montagnac G, de Forges H, Smythe E, Gueudry C, Romao M, Salamero J, Chavrier P (2011). Decoupling of activation and effector binding underlies ARF6 priming of fast endocytic recycling. Curr Biol 21, 574–579. Crossref, MedlineGoogle Scholar
  • Morinaga N, Tsai SC, Moss J, Vaughan M (1996). Isolation of a brefeldin A-inhibited guanine nucleotide-exchange protein for ADP ribosylation factor (ARF) 1 and ARF3 that contains a Sec7-like domain. Proc Natl Acad Sci USA 93, 12856–12860. Crossref, MedlineGoogle Scholar
  • Mossessova E, Corpina RA, Goldberg J (2003). Crystal structure of ARF1*Sec7 complexed with Brefeldin A and its implications for the guanine nucleotide exchange mechanism. Mol Cell 12, 1403–1411. Crossref, MedlineGoogle Scholar
  • Niu TK, Pfeifer AC, Lippincott-Schwartz J, Jackson CL (2005). Dynamics of GBF1, a Brefeldin A-sensitive Arf1 exchange factor at the Golgi. Mol Biol Cell 16, 1213–1222. LinkGoogle Scholar
  • Oda K, Fujiwara T, Ikehara Y (1990). Brefeldin A arrests the intracellular transport of viral envelope proteins in primary cultured rat hepatocytes and HepG2 cells. Biochem J 265, 161–167. Crossref, MedlineGoogle Scholar
  • Orci L, Tagaya M, Amherdt M, Perrelet A, Donaldson JG, Lippincott-Schwartz J, Klausner RD, Rothman JE (1991). Brefeldin A, a drug that blocks secretion, prevents the assembly of non-clathrin-coated buds on Golgi cisternae. Cell 64, 1183–1195. Crossref, MedlineGoogle Scholar
  • Pacheco-Rodriguez G, Moss J, Vaughan M (2002). BIG1 and BIG2: brefeldin A-inhibited guanine nucleotide-exchange proteins for ADP-ribosylation factors. Methods Enzymol 345, 397–404. Crossref, MedlineGoogle Scholar
  • Padilla PI, Pacheco-Rodriguez G, Moss J, Vaughan M (2004). Nuclear localization and molecular partners of BIG1, a brefeldin A-inhibited guanine nucleotide-exchange protein for ADP-ribosylation factors. Proc Natl Acad Sci USA 101, 2752–2757. Crossref, MedlineGoogle Scholar
  • Pasqualato S, Menetrey J, Franco M, Cherfils J (2001). The structural GDP/GTP cycle of human Arf6. EMBO Rep 2, 234–238. Crossref, MedlineGoogle Scholar
  • Pernet-Gallay K, Antony C, Johannes L, Bornens M, Goud B, Rios RM (2002). The overexpression of GMAP-210 blocks anterograde and retrograde transport between the ER and the Golgi apparatus. Traffic 3, 822–832. Crossref, MedlineGoogle Scholar
  • Peters PJ, Hsu VW, Ooi CE, Finazzi D, Teal SB, Oorschot V, Donaldson JG, Klausner RD (1995). Overexpression of wild-type and mutant ARF1 and ARF6: distinct perturbations of nonoverlapping membrane compartments. J Cell Biol 128, 1003–1017. Crossref, MedlineGoogle Scholar
  • Peurois F, Veyron S, Ferrandez Y, Ladid I, Benabdi S, Zeghouf M, Peyroche G, Cherfils J (2017). Characterization of the activation of small GTPases by their GEFs on membranes using artificial membrane tethering. Biochem J 474, 1259–1272. Crossref, MedlineGoogle Scholar
  • Pocognoni CA, Viktorova EG, Wright J, Meissner JM, Sager G, Lee E, Belov GA, Sztul E (2018). Highly conserved motifs within the large Sec7 ARF guanine nucleotide exchange factor GBF1 target it to the Golgi and are critical for GBF1 activity. Am J Physiol Cell Physiol 314, C675–C689. Crossref, MedlineGoogle Scholar
  • Presley JF, Ward TH, Pfeifer AC, Siggia ED, Phair RD, Lippincott-Schwartz J (2002). Dissection of COPI and Arf1 dynamics in vivo and role in Golgi membrane transport. Nature 417, 187–193. Crossref, MedlineGoogle Scholar
  • Quilty D, Chan CJ, Yurkiw K, Bain A, Babolmorad G, Melancon P (2018). The Arf-GDP-regulated recruitment of GBF1 to Golgi membranes requires domains HDS1 and HDS2 and a Golgi-localized protein receptor. J Cell Sci 132. MedlineGoogle Scholar
  • Radhakrishna H, Klausner RD, Donaldson JG (1996). Aluminum fluoride stimulates surface protrusions in cells overexpressing the ARF6 GTPase. J Cell Biol 134, 935–947. Crossref, MedlineGoogle Scholar
  • Renault L, Guibert B, Cherfils J (2003). Structural snapshots of the mechanism and inhibition of a guanine nucleotide exchange factor. Nature 426, 525–530. Crossref, MedlineGoogle Scholar
  • Rios RM, Sanchis A, Tassin AM, Fedriani C, Bornens M (2004). GMAP-210 recruits gamma-tubulin complexes to cis-Golgi membranes and is required for Golgi ribbon formation. Cell 118, 323–335. Crossref, MedlineGoogle Scholar
  • Robineau S, Chabre M, Antonny B (2000). Binding site of brefeldin A at the interface between the small G protein ADP-ribosylation factor 1 (ARF1) and the nucleotide-exchange factor Sec7 domain. Proc Natl Acad Sci USA 97, 9913–9918. Crossref, MedlineGoogle Scholar
  • Robinson MS (2004). Adaptable adaptors for coated vesicles. Trends Cell Biol 14, 167–174. Crossref, MedlineGoogle Scholar
  • Robinson MS (2015). Forty years of clathrin-coated vesicles. Traffic 16, 1210–1238. Crossref, MedlineGoogle Scholar
  • Saenz JB, Sun WJ, Chang JW, Li J, Bursulaya B, Gray NS, Haslam DB (2009). Golgicide A reveals essential roles for GBF1 in Golgi assembly and function. Nat Chem Biol 5, 157–165. Crossref, MedlineGoogle Scholar
  • Santy LC, Casanova JE (2001). Activation of ARF6 by ARNO stimulates epithelial cell migration through downstream activation of both Rac1 and phospholipase D. J Cell Biol 154, 599–610. Crossref, MedlineGoogle Scholar
  • Santy LC, Frank SR, Casanova JE (2001). Expression and analysis of ARNO and ARNO mutants and their effects on ADP-ribosylation factor (ARF)-mediated actin cytoskeletal rearrangements. Methods Enzymol 329, 256–264. Crossref, MedlineGoogle Scholar
  • Schafer DA, D’Souza-Schorey C, Cooper JA (2000). Actin assembly at membranes controlled by ARF6. Traffic 1, 892–903. Crossref, MedlineGoogle Scholar
  • Sheen VL, Ganesh VS, Topcu M, Sebire G, Bodell A, Hill RS, Grant PE, Shugart YY, Imitola J, Khoury SJ, et al. (2004). Mutations in ARFGEF2 implicate vesicle trafficking in neural progenitor proliferation and migration in the human cerebral cortex. Nat Genet 36, 69–76. Crossref, MedlineGoogle Scholar
  • Shen X, Hong MS, Moss J, Vaughan M (2007). BIG1, a brefeldin A-inhibited guanine nucleotide-exchange protein, is required for correct glycosylation and function of integrin beta1. Proc Natl Acad Sci USA 104, 1230–1235. Crossref, MedlineGoogle Scholar
  • Shen X, Li CC, Aponte AM, Shen RF, Billings EM, Moss J, Vaughan M (2012). Brefeldin A-inhibited ADP-ribosylation factor activator BIG2 regulates cell migration via integrin beta1 cycling and actin remodeling. Proc Natl Acad Sci USA 109, 14464–14469. Crossref, MedlineGoogle Scholar
  • Shen X, Xu KF, Fan Q, Pacheco-Rodriguez G, Moss J, Vaughan M (2006). Association of brefeldin A-inhibited guanine nucleotide-exchange protein 2 (BIG2) with recycling endosomes during transferrin uptake. Proc Natl Acad Sci USA 103, 2635–2640. Crossref, MedlineGoogle Scholar
  • Shin HW, Morinaga N, Noda M, Nakayama K (2004). BIG2, a guanine nucleotide exchange factor for ADP-ribosylation factors: its localization to recycling endosomes and implication in the endosome integrity. Mol Biol Cell 15, 5283–5294. LinkGoogle Scholar
  • Shin HW, Shinotsuka C, Nakayama K (2005). Expression of BIG2 and analysis of its function in mammalian cells. Methods Enzymol 404, 206–215. Crossref, MedlineGoogle Scholar
  • Shinotsuka C, Waguri S, Wakasugi M, Uchiyama Y, Nakayama K (2002a). Dominant-negative mutant of BIG2, an ARF-guanine nucleotide exchange factor, specifically affects membrane trafficking from the trans-Golgi network through inhibiting membrane association of AP-1 and GGA coat proteins. Biochem Biophys Res Commun 294, 254–260. Crossref, MedlineGoogle Scholar
  • Shinotsuka C, Yoshida Y, Kawamoto K, Takatsu H, Nakayama K (2002b). Overexpression of an ADP-ribosylation factor-guanine nucleotide exchange factor, BIG2, uncouples brefeldin A-induced adaptor protein-1 coat dissociation and membrane tubulation. J Biol Chem 277, 9468–9473. Crossref, MedlineGoogle Scholar
  • Shrivastava-Ranjan P, Faundez V, Fang G, Rees H, Lah JJ, Levey AI, Kahn RA (2008). Mint3/X11gamma is an ADP-ribosylation factor-dependent adaptor that regulates the traffic of the Alzheimer’s precursor protein from the trans-Golgi network. Mol Biol Cell 19, 51–64. LinkGoogle Scholar
  • Spang A (2016). Membrane tethering complexes in the endosomal system. Front Cell Dev Biol 4, 35. Crossref, MedlineGoogle Scholar
  • Styers ML, O’Connor AK, Grabski R, Cormet-Boyaka E, Sztul E (2008). Depletion of β-COP reveals a role for COP-I in compartmentalization of secretory compartments and in biosynthetic transport of caveolin-1. Am J Physiol Cell Physiol 294, C1485–C1498. Crossref, MedlineGoogle Scholar
  • Suzuki A, Arikawa C, Kuwahara Y, Itoh K, Watanabe M, Watanabe H, Suzuki T, Funakoshi Y, Hasegawa H, Kanaho Y (2010). The scaffold protein JIP3 functions as a downstream effector of the small GTPase ARF6 to regulate neurite morphogenesis of cortical neurons. FEBS Lett 584, 2801–2806. Crossref, MedlineGoogle Scholar
  • Szul T, Garcia-Mata R, Brandon E, Shestopal S, Alvarez C, Sztul E (2005). Dissection of membrane dynamics of the ARF-guanine nucleotide exchange factor GBF1. Traffic 6, 374–385. Crossref, MedlineGoogle Scholar
  • Szul T, Grabski R, Lyons S, Morohashi Y, Shestopal S, Lowe M, Sztul E (2007). Dissecting the role of the ARF guanine nucleotide exchange factor GBF1 in Golgi biogenesis and protein trafficking. J Cell Sci 120(Pt 22), 3929–3940. Crossref, MedlineGoogle Scholar
  • Togawa A, Morinaga N, Ogasawara M, Moss J, Vaughan M (1999). Purification and cloning of a brefeldin A-inhibited guanine nucleotide-exchange protein for ADP-ribosylation factors. J Biol Chem 274, 12308–12315. Crossref, MedlineGoogle Scholar
  • Turner CE, Brown MC (2001). Cell motility: ARNOand ARF6 at the cutting edge. Curr Biol 11, R875–R877. Crossref, MedlineGoogle Scholar
  • Tuuf J, Mattjus P (2014). Membranes and mammalian glycolipid transferring proteins. Chem Phys Lipids 178, 27–37. Crossref, MedlineGoogle Scholar
  • van Vliet C, Thomas EC, Merino-Trigo A, Teasdale RD, Gleeson PA (2003). Intracellular sorting and transport of proteins. Prog Biophys Mol Biol 83, 1–45. Crossref, MedlineGoogle Scholar
  • Volpicelli-Daley LA, Li Y, Zhang CJ, Kahn RA (2005). Isoform-selective effects of the depletion of ADP-ribosylation factors 1–5 on membrane traffic. Mol Biol Cell 16, 4495–4508. LinkGoogle Scholar
  • Williams D, Hicks SW, Machamer CE, Pessin JE (2006). Golgin-160 is required for the Golgi membrane sorting of the insulin-responsive glucose transporter GLUT4 in adipocytes. Mol Biol Cell 17, 5346–5355. LinkGoogle Scholar
  • Wright J, Kahn RA, Sztul E (2014). Regulating the large Sec7 ARF guanine nucleotide exchange factors: the when, where and how of activation. Cell Mol Life Sci 71, 3419–3438. Crossref, MedlineGoogle Scholar
  • Yoshino A, Bieler BM, Harper DC, Cowan DA, Sutterwala S, Gay DM, Cole NB, McCaffery JM, Marks MS (2003). A role for GRIP domain proteins and/or their ligands in structure and function of the trans Golgi network. J Cell Sci 116(Pt 21), 4441–4454. Crossref, MedlineGoogle Scholar
  • Zeeh JC, Zeghouf M, Grauffel C, Guibert B, Martin E, Dejaegere A, Cherfils J (2006). Dual specificity of the interfacial inhibitor brefeldin a for arf proteins and sec7 domains. J Biol Chem 281, 11805–11814. Crossref, MedlineGoogle Scholar
  • Zhao X, Claude A, Chun J, Shields DJ, Presley JF, Melancon P (2006). GBF1, a cis-Golgi and VTCs-localized ARF-GEF, is implicated in ER-to-Golgi protein traffic. J Cell Sci 119(Pt 18), 3743–3753. Crossref, MedlineGoogle Scholar
  • Zhao X, Lasell TK, Melancon P (2002). Localization of large ADP-ribosylation factor-guanine nucleotide exchange factors to different Golgi compartments: evidence for distinct functions in protein traffic. Mol Biol Cell 13, 119–133. LinkGoogle Scholar