The Rab GTPase-activating proteins (GAP) Gyp5p and Gyl1p are involved in the control of polarized exocytosis at the small-bud stage in Saccharomyces cerevisiae. Both Gyp5p and Gyl1p interact with the N-Bin1/Amphiphysin/Rvs167 (BAR) domain protein Rvs167p, but the biological function of this interaction is unclear. We show here that Gyp5p and Gyl1p recruit Rvs167p to the small-bud tip, where it plays a role in polarized exocytosis. In gyp5Δgyl1Δ cells, Rvs167p is not correctly localized to the small-bud tip. Both P473L mutation in the SH3 domain of Rvs167p and deletion of the proline-rich regions of Gyp5p and Gyl1p disrupt the interaction of Rvs167p with Gyp5p and Gyl1p and impair the localization of Rvs167p to the tips of small buds. We provide evidence for the accumulation of secretory vesicles in small buds of rvs167Δ cells and for defective Bgl2p secretion in rvs167Δ cultures enriched in small-budded cells at 13°C, implicating Rvs167p in polarized exocytosis. Moreover, both the accumulation of secretory vesicles in Rvs167p P473L cells cultured at 13°C and secretion defects in cells producing Gyp5p and Gyl1p without proline-rich regions strongly suggest that the function of Rvs167p in exocytosis depends on its ability to interact with Gyp5p and Gyl1p.
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http://dx.doi.org/10.1111/j.1600-0854.2011.01218.x | DOI Listing |
Traffic
August 2011
Univ Paris-Sud, Institut de Génétique et Microbiologie, CNRS UMR8621, Bâtiment 400, Orsay F-91405, France.
The Rab GTPase-activating proteins (GAP) Gyp5p and Gyl1p are involved in the control of polarized exocytosis at the small-bud stage in Saccharomyces cerevisiae. Both Gyp5p and Gyl1p interact with the N-Bin1/Amphiphysin/Rvs167 (BAR) domain protein Rvs167p, but the biological function of this interaction is unclear. We show here that Gyp5p and Gyl1p recruit Rvs167p to the small-bud tip, where it plays a role in polarized exocytosis.
View Article and Find Full Text PDFTraffic
April 2008
Institut de Génétique et Microbiologie, Université Paris Sud 11, CNRS UMR8621, Bâtiment 400, F-91405 Orsay Cedex, France.
Gyp5p and Gyl1p are two members of the Ypt/Rab guanosine triphosphatases-activating proteins involved in the control of polarized exocytosis in Saccharomyces cerevisiae. We had previously shown that Gyp5p and Gyl1p colocalize at the sites of polarized growth and belong to the same complex in subcellular fractions enriched in plasma membrane or secretory vesicles. Here, we investigate the interaction between Gyp5p and Gyl1p as well as the mechanism of their localization to the sites of polarized growth.
View Article and Find Full Text PDFGenetics
June 2005
Department of Molecular and Medical Genetics, University of Toronto, Ontario, Canada.
We have used affinity chromatography to identify two proteins that bind to the SH3 domain of the actin cytoskeleton protein Rvs167p: Gyp5p and Gyl1p. Gyp5p has been shown to be a GTPase activating protein (GAP) for Ypt1p, a Rab GTPase involved in ER to Golgi trafficking; Gyl1p is a protein that resembles Gyp5p and has recently been shown to colocalize with and belong to the same protein complex as Gyp5p. We show that Gyl1p and Gyp5p interact directly with each other, likely through their carboxy-terminal coiled-coil regions.
View Article and Find Full Text PDFJ Cell Sci
September 2004
Institut de Génétique et Microbiologie, CNRS-UMR 8621, Université Paris XI, 91 405 Orsay Cédex, France.
We report here elements for functional characterization of two members of the Saccharomyces cerevisiae Ypt/Rab GTPase activating proteins family (GAP): Gyp5p, a potent GAP in vitro for Ypt1p and Sec4p, and the protein Ymr192wp/APP2 that we propose to rename Gyl1p (GYp like protein). Immunofluorescence experiments showed that Gyp5p and Gyl1p partly colocalize at the bud emergence site, at the bud tip and at the bud neck during cytokinesis. Subcellular fractionation and co-immunoprecipitation experiments showed that Gyp5p and Gyl1p co-fractionate with post-Golgi vesicles and plasma membrane, and belong to the same protein complexes in both localizations.
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