Gyp5p and Gyl1p are involved in the control of polarized exocytosis in budding yeast
Gyp5p and Gyl1p are involved in the control of polarized exocytosis in budding yeast
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DOI：
10.1242/jcs.01349
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发表时间：
2004-09-15
影响因子：
4
通讯作者：
Cuif, MH
中科院分区：
文献类型：
--
作者：
Chesneau, L;Dupré, S;Cuif, MH
我们在这里报告的元件的功能特性的两个成员的酿酒酵母Ypt/Rab GT3激活蛋白家族（GAP）：Gyp 5 p，一个有效的GAP在体外的Ypt 1 p和Sec 4p，和蛋白质Ymr 192 wp/APP 2，我们建议重命名Gy 11 p（GYp样蛋白）。免疫荧光实验表明，Gyp 5 p和Gy 11 p在胞质分裂过程中部分共定位于芽萌发部位、芽尖和芽颈。亚细胞分级分离和免疫共沉淀实验表明，Gyp 5 p和Gy 11 p与高尔基体后囊泡和质膜共沉淀，并且在两种定位中属于相同的蛋白复合物。我们发现，通过免疫共沉淀实验，Gyp 5 p的一部分与Sec 4p，一个小的参与胞吐的GT3相互作用，和Gy 11 p的一部分协会在质膜与Gyp 5 p/Sec 4p复合物。我们还发现GYP 5与编码Sec 4p交换因子的SEC 2在遗传上相互作用。对在13 ℃下生长的gyp 5Deltagy 11 Delta突变体的检查揭示了轻微的生长缺陷、分泌缺陷和小出芽细胞中分泌囊泡的积累。这些数据表明，Gyp 5 p和Gy 11 p参与控制极化胞吐。
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 Gy11p (GYp like protein). Immunofluorescence experiments showed that Gyp5p and Gy11p 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 Gy11p co-fractionate with post-Golgi vesicles and plasma membrane, and belong to the same protein complexes in both localizations. We found by co-immunoprecipitation experiments that a fraction of Gyp5p interacts with Sec4p, a small GTPase involved in exocytosis, and that a fraction of Gy11p associates at the plasma membrane with the Gyp5p/Sec4p complexes. We showed also that GYP5 genetically interacts with SEC2, which encodes the Sec4p exchange factor. Examination of the gyp5Deltagy11Delta mutants grown at 13 degreesC revealed a slight growth defect, a secretion defect and an accumulation of secretory vesicles in the small-budded cells. These data suggest that Gyp5p and Gy11p are involved in control of polarized exocytosis.