![[Feedback]](/icons/banner/feedbackACT.gif){kind=icon}
![[For Subscribers]](/icons/banner/subscriberACT.gif){kind=icon}
![[Archive]](/icons/banner/archiveACT.gif){kind=icon}
![[Search]](/icons/banner/searchACT.gif){kind=icon}
![[Contents]](/icons/banner/tocACT.gif){kind=icon}
|
|
|
|
|
||
Vol. 16, Issue 10, 4463-4472, October 2005
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
* Department of Cell Biology University of Virginia Health System, School of Medicine, Charlottesville, VA 22908;
Department of Molecular Physiology and Biological Physics, University of Virginia Health System, School of Medicine, Charlottesville, VA 22908
Submitted March 18, 2005;
Revised June 30, 2005;
Accepted July 8, 2005
Monitoring Editor: Benjamin Glick
SNAP receptor (SNARE)-mediated fusion is regarded as a core event in exocytosis. Exocytosis is supported by other proteins that set up SNARE interactions between secretory vesicle and plasma membranes or facilitate fusion pore formation. Secretory carrier membrane proteins (SCAMPs) are candidate proteins for functioning in these events. In neuroendocrine PC12 cells, SCAMP2 colocalizes on the cell surface with three other proteins required for dense-core vesicle exocytosis: phospholipase D1 (PLD1), the small GTPase Arf6, and Arf6 guanine nucleotide exchange protein ARNO. Arf6 and PLD1 coimmunoprecipitate (coIP) with SCAMP2. These associations have been implicated in exocytosis by observing enhanced coIP of Arf6 with SCAMP2 after cell depolarization and in the presence of guanosine 5'-O-(3-thio)triphosphate and by inhibition of coIP by a SCAMP-derived peptide that inhibits exocytosis. The peptide also suppresses PLD activity associated with exocytosis. Using amperometry to analyze exocytosis, we show that expression of a point mutant of SCAMP2 that exhibits decreased association with Arf6 and of mutant Arf6 deficient in activating PLD1 have the same inhibitory effects on early events in membrane fusion. However, mutant SCAMP2 also uniquely inhibits fusion pore dilation. Thus, SCAMP2 couples Arf6-stimulated PLD activity to exocytosis and links this process to formation of fusion pores.
The online version of this article contains supplemental material at MBC Online (http://www.molbiolcell.org).
These authors contributed equally to this work.
Address correspondence to: David Castle (jdc4r{at}virginia.edu).
This article has been cited by other articles:
|
|
 |
|
  H. Liao, J. Zhang, S. Shestopal, G. Szabo, A. Castle, and D. Castle Nonredundant function of secretory carrier membrane protein isoforms in dense core vesicle exocytosis Am J Physiol Cell Physiol, March 1, 2008; 294(3): C797 - C809. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. K. Lam, C. L. Siu, S. Hillmer, S. Jang, G. An, D. G. Robinson, and L. Jiang Rice SCAMP1 Defines Clathrin-Coated, trans-Golgi-Located Tubular-Vesicular Structures as an Early Endosome in Tobacco BY-2 Cells PLANT CELL, January 1, 2007; 19(1): 296 - 319. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. K. Muller, O. Wiborg, and J. Haase Subcellular Redistribution of the Serotonin Transporter by Secretory Carrier Membrane Protein 2 J. Biol. Chem., September 29, 2006; 281(39): 28901 - 28909. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Abraham, H. Hutter, M. T. Palfreyman, G. Spatkowski, R. M. Weimer, R. Windoffer, E. M. Jorgensen, and R. E. Leube Synaptic tetraspan vesicle membrane proteins are conserved but not needed for synaptogenesis and neuronal function in Caenorhabditis elegans PNAS, May 23, 2006; 103(21): 8227 - 8232. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. Nakanishi, M. Morishita, C. L. Schwartz, A. Coluccio, J. Engebrecht, and A. M. Neiman Phospholipase D and the SNARE Sso1p are necessary for vesicle fusion during sporulation in yeast. J. Cell Sci., April 1, 2006; 119(Pt 7): 1406 - 1415. [Abstract] [Full Text] [PDF]
|
|
