YPTL GTPASE AND VESICULAR TRANSPORT

描述：阐明蛋白质被分类的机制 正确的隔室是我们理解细胞生长的基础。 细胞内隔室之间的蛋白质运输是由 膜小泡，而Rab/YPT家族的GTP酶在 调控这些囊泡在所有真核细胞中的靶向。这个 该项目的长期目标是了解囊泡如何运输 Rab/Ypt GTP酶的作用和具体作用(S) 监管。囊泡融合的基础机制是高度保守的 在酵母和人类之间。这项提案专门针对 分泌物中的YPT GTP酶，以面包酵母的Ypt1为模型。 拟议的研究将集中在与YPT GTP酶相互作用的蛋白质上 以及它们作为效应者或调节者发挥作用的机制。 现有的和新鉴定的基因将被检查它们的作用 在蛋白质运输中分析突变体潜在的分泌缺陷，以及 研究他们的产品的细胞内定位。过度表达 研究将被用来区分假定的调节器 Ypt1的核苷酸循环，来自作为Ypt1效应器的那些， 通常不会影响这种循环。这些基因将被用来 回答以下问题：1)效应器蛋白的作用是什么 YPT GTP酶？Rab蛋白和其他ras相关的gtp酶一样，被认为 通过调节下游效应器来发挥作用 依赖于GTP的方式，将信号从GTP绑定的形式传输到 膜对接和/或融合设备。为了确定确切的机制 Ypt1效应器的功能，这些基因中突变的行为 将检查粘连萌芽、靶向、脱涂层或 融合，以及它们与Ypt1相互作用的性质。2)角色是什么 调节YPT GTP酶核苷酸循环的辅助因素有哪些？ 在GTP和GDP绑定的表单之间循环，由附件促进 因子，被认为对RAB功能至关重要。然而，人们对此知之甚少 关于这些因素如何找到他们的RAB目标，他们如何促进 核苷酸交换和水解。假定的监管者将接受测试 这些活动。解决有关其特殊性的问题，并 作用机制，它们与YPT和其他蛋白质的相互作用 分泌的功能将在体内和体外进行检测。最后， 我们将探索胞外YPT蛋白之间的相互作用。

DESCRIPTION: Elucidation of the mechanism by which proteins are sorted into the correct compartments is fundamental to our understanding of cell growth. Protein transport between intracellular compartments is mediated by membranous vesicles, and the rab/Ypt family of GTPases plays a major role in regulating the targeting of these vesicles in all eukaryotic cells. The long term goal of the project is to understand how vesicular transport operates and the specific role(s) that rab/Ypt GTPases have in its regulation. Mechanisms that underlie vesicle fusion are highly conserved between yeast and man. This proposal specifically addreses the function of Ypt GTPases in secretion, using Ypt1 of baker's yeast as a model. The proposed research will focus on proteins that interact with Ypt GTPases and the mechanisms by which they function as effectors or regulators. Existing as well as newly identified genes, will be examined for their role in protein transport analyzing potential secretory defects in mutants, and studying intracellular localization of their products. Overexpression studies will be used to distinguish putative regulators that modulate nucleotide cycling of Ypt1, from those that funciton as Ypt1 effectors, which typically do not affect this cycling. These genes will be used to address the following questions: 1) What are the roles of effector proteins of Ypt GTPases? Rab proteins, like other ras-related GTPases, are believed to function through the regulation of downstream effectors in a GTP-dependent manner, to transmit a signal from the GTP-bound form to the membrane docking and/or fusion apparatus. To determine the exact mechanism by which Ypt1 effectors function, the behavior of mutants in these genes will be examined with respect to visicle budding, targeting, uncoating or fusion, and the nature of their interaction with Ypt1. 2) What is the role of accessory factors that regulate nucleotide cycling of Ypt GTPases? Cycling between the GTP- and GDP-bound forms, facilitated by accessory factors, is considered crucial for rab function. However, little is known regarding how these factors find their rab targets of how they facilitate nucleotide exchange and hydrolysis. Putative regulators will be tested for these activities. To resolve issues concerning their spoecificity and mechanism of action, their interactions with Ypt and other proteins that funciton in secretion will be examined in vivo and in vitro. Finally, interaction among exocytic Ypt proteins themselves will be explored.