Regulation of Cell Polarity and Exocytosis

描述（由申请人提供）：本提案的总体目标是了解真核细胞将极化生长和分泌导向细胞表面特定位点的机制，以及这如何与整体细胞极性协调。从我们的实验室和其他人以前的工作已经牵连的Lgl/Sro 7和Rho/Cdc 42蛋白家族的成员的因素，在两个膜运输到细胞表面和细胞极性在一些系统中具有重要作用。在酵母细胞表面上的运输的空间调节需要Rho/Cdc 42定位的特定模式以及Lgl/Sro 7蛋白的囊泡束缚和融合功能的紧密调节。在本建议中，我们将审查结构 Cdc 42和Rho 3 GT3蛋白中的元件，其对于其不同的定位模式至关重要，并且限定了用于Cdc 42再循环和运输至细胞表面的特定内吞因子和途径。最后，我们将建立在我们最近发现的一个Rab-dependent囊泡对接功能的Sro 7解剖内和分子间的调节Sro 7的囊泡对接和融合的双重功能。

DESCRIPTION (provided by applicant): The overall goal of this proposal is to understand the mechanism by which eukaryotic cells direct polarized growth and secretion to specific sites on the cell surface and how this is coordinated with overall cell polarity. Previous work from our laboratory and others has implicated members of the Lgl/Sro7 and Rho/Cdc42 protein families as factors that have important roles in both membranes trafficking to the cell surface and cell polarity in a number of systems. Spatial regulation of trafficking on the cell surface in yeast requires specific patterns of Rho/Cdc42 localization as well as tight regulation of vesicle tethering and fusion functions of Lgl/Sro7 protein. In this proposal we will examine the structural elements in Cdc42 and Rho3 GTPase proteins that are critical for their distinct patterns of localization and define the specific endocytic factors and pathways utilized for recycling and trafficking of Cdc42 to the cell surface. Finally we will build on our recent discovery of a Rab-dependent vesicle docking function of Sro7 to dissect both the intra and intermolecular regulation of Sro7's dual functions in vesicle docking and fusion.