Role of Ypt GTPases in Vesicular transport

描述(申请人摘要)：分泌途径是 细胞与其环境的相互作用，因为这是 蛋白质和多肽被释放到周围的蜂蜜、受体、离子中 通道和离子泵呈现在质膜上，而配体和 受体是内化的。阐明调节这一过程的机制 通路与多种疾病有关，这些疾病是由受损的 一种物质的运输，这种物质在糖尿病和糖尿病中是必不可少的 Cftr在囊性纤维化中，或在阿尔茨海默病中作为β-淀粉样蛋白有害。 在分泌途径中，蛋白质在细胞内运输 隔室通过膜性小泡。小分子GTP酶在细胞周期中起关键作用 对这种囊泡贩运的监管。这些机械和机械 下面的囊泡形成，靶向和融合是高度保守的 酵母和人类。我们将使用酵母作为模型系统来解决这些复杂的问题 问题，因为这种有机体允许使用强大的遗传方法 除了分子和细胞外。我们的长期目标是了解 YPT/Rab GTP酶如何调节和协调分泌的离散步骤 路径。拟议中的研究将集中在具有以下功能的蛋白质上： YPT GTP酶的调节者或效应者。它们将被用来解决三个问题 重要的问题。1)YPT核苷酸调节子的作用是什么 循环在YPT介导的蛋白质运输中起作用？在GTP和GTP之间骑自行车 在附件因素的推动下，与GDP挂钩的表格被认为对 YPT/RAB函数。然而，人们对这些因素的定位知之甚少。 它们的YPT/Rab靶标，促进核苷酸交换或水解，并影响 YPT GTP酶功能。为了解决这些问题，监管机构的本地化， 它们的功能以及它们与YPT GTP酶的相互作用将在 体内和体外。2)YPT蛋白在GTPase级联中起作用吗？这 已有的假说表明YPT蛋白影响细胞的核苷酸循环 其他GTP酶协调分泌途径的离散步骤。这个 GTPase级联的存在和性质将首先在#年进行研究 在体外，它们的作用将在体内进行测试。3)效应器扮演什么角色 YPT GTP酶中有哪些在蛋白质转运中起作用？Ypt/Rab蛋白和其他GTP酶一样， 据信通过招募下游效应器发挥作用， 它们将信号从GTP结合的GTP酶传递到膜对接和/或 聚变装置。为了确定YPT效应器发挥作用的机制， 我们将研究YPT效应基因突变对囊泡萌发的影响， 靶向，或融合，以及它们与YPT GTP酶相互作用的性质。

DESCRIPTION (APPLICANT'S ABSTRACT): The secretory pathway is central to the interaction of cells with their environment as it is the route by which proteins and peptides are released into the surrounding melieu, receptors, ion channels and ion pumps are presented on the plasma membrane, and ligands and receptors are internalized. Elucidation of the mechanisms that regulate this pathway is relevant for a variety of diseases that are caused by impaired transport of a substance that is either essential as insulin in diabetes and CFTR in cystic fibrosis, or detrimental as beta-amyloid in Alzheimer disease. In the secretory pathway proteins are transported between intracellular compartments via membranous vesicles. Small GTPases play a key role in the regulation of this vesicular trafficking. The mechanisms and machinery that underlie vesicle formation, targeting and fusion are highly conserved between yeast and man. We will use yeast as a model system to address these complicated issues, since this organism allows the use of powerful genetic approaches in addition to molecular and cellular ones. Our long term goal is to understand how Ypt/Rab GTPases regulate and coordinate the discrete steps of the secretory pathway. The proposed research will focus on proteins that function as regulators or effectors for Ypt GTPases. They will be used to address three important questions. 1) What is the role that regulators of Ypt nucleotide cycling play in Ypt-mediated protein transport? Cycling between the GTP- and GDP-bound forms, facilitated by accessory factors, is considered crucial for Ypt/Rab function. However, little is known regarding how these factors locate their Ypt/Rab targets, facilitate nucleotide exchange or hydrolysis, and affect Ypt GTPase function. To resolve these issues, the localization of regulators, their function and their interaction with Ypt GTPases will be examined both in vivo and in vitro. 2) Do Ypt proteins function in GTPase cascades? This existing hypothesis suggests that Ypt proteins affect nucleotide cycling of other GTPases to coordinate discrete steps of the secretory pathway. The existence and the nature of GTPase cascades will be first investigated in vitro, and later their role will be tested in vivo. 3) What role do effectors of Ypt GTPases play in protein transport? Ypt/Rab proteins, like other GTPases, are believed to function through the recruitment of down-stream effectors, which transmit signals from the GTP-bound GTPase to the membrane docking and/or fusion apparatus. To determine the mechanism by which Ypt effectors function, we will study the effect of mutations in Ypt effector genes on vesicle budding, targeting, or fusion, and the nature of their interaction with Ypt GTPases.