QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

Vol. 17, Issue 7, 3281-3290, July 2006

This Article Full Text Full Text (PDF) Supplemental Material All Versions of this Article: E06-02-0106v1 17/7/3281    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Xiao, J. Articles by Graham, T. R. Search for Related Content PubMed PubMed Citation Articles by Xiao, J. Articles by Graham, T. R.

Dissection of Swa2p/Auxilin Domain Requirements for Cochaperoning Hsp70 Clathrin-uncoating Activity In Vivo

Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235-1634

Submitted February 7, 2006; Revised April 17, 2006; Accepted April 27, 2006
Monitoring Editor: Sandra Lemmon

The auxilin family of J-domain proteins load Hsp70 onto clathrin-coated vesicles (CCVs) to drive uncoating. In vitro, auxilin function requires its ability to bind clathrin and stimulate Hsp70 ATPase activity via its J-domain. To test these requirements in vivo, we performed a mutational analysis of Swa2p, the yeast auxilin ortholog. Swa2p is a modular protein with three N-terminal clathrin-binding (CB) motifs, a ubiquitin association (UBA) domain, a tetratricopeptide repeat (TPR) domain, and a C-terminal J-domain. In vitro, clathrin binding is mediated by multiple weak interactions, but a Swa2p truncation lacking two CB motifs and the UBA domain retains nearly full function in vivo. Deletion of all CB motifs strongly abrogates clathrin disassembly but does not eliminate Swa2p function in vivo. Surprisingly, mutation of the invariant HPD motif within the J-domain to AAA only partially affects Swa2p function. Similarly, a TPR point mutation (G388R) causes a modest phenotype. However, Swa2p function is abolished when these TPR and J mutations are combined. The TPR and J-domains are not functionally redundant because deletion of either domain renders Swa2p nonfunctional. These data suggest that the TPR and J-domains collaborate in a bipartite interaction with Hsp70 to regulate its activity in clathrin disassembly.

The online version of this article contains supplemental material at MBC Online (http://www.molbiolcell.org).

Address correspondence to: Todd R. Graham ( tr.graham{at}vanderbilt.edu)

This article has been cited by other articles:

				C. Sahi and E. A. Craig Network of general and specialty J protein chaperones of the yeast cytosol PNAS, April 24, 2007; 104(17): 7163 - 7168. [Abstract] [Full Text] [PDF]