GTPAse Regulation of ER Export

ER 出口的 GTPA 酶监管

• 批准号: 6784109
• 负责人: William Edward Balch
• 金额: $ 42.23万
• 依托单位: SCRIPPS RESEARCH INSTITUTE, THE
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-08-01 至 2007-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6784109
• 关键词: Vesiculovirus; X ray crystallography; endoplasmic reticulum; enzyme activity; enzyme mechanism; genetic models; genetically modified animals; guanine nucleotide exchange factors; guanosinetriphosphatases; intracellular transport; laboratory mouse; laboratory rabbit; laboratory rat; protein protein interaction; protein structure function; site directed mutagenesis; vesicle /vacuole; virus protein

DESCRIPTION (provided by applicant): Our long-range goal is to understand the roles of membrane-bound and cytosolic proteins that direct the sorting of cargo into COPII vesicles budding from endoplasmic reticulum (ER) of mammalian cells. The mechanism by which cargo is selected and concentrated during export is unknown. To address this goal, we will focus on the central role of the Sar1 GTPase and its upstream and downstream effectors in cargo selection. Aim I. Molecular basis for Sar1 activation leading to transitional element formation. We will examine the mechanism by which Sarl directs the assembly of export sites through interaction with the mammalian Sec12 guanine nucleotide exchange factor (GEF) to generate tubular elements that form using a KIF-dependent process. Specific Aim II. Biochemical basis for cargo selection. We will explore the hypothesis that novel components of pre budding complexes are part of a protein machine that coordinates cargo selection with other aspects of ER function to select cargo into COPII vesicles. We will address the molecular basis for cargo recognition, Sec23/24 recruitment and coat polymerization by Sar1, and generate transgenic mouse models to pursue the unique functions of mammalian Sec24 (A-D) isoforms. Specific Aim Ill. Vesicle maturation. We will explore the basis for coordination of cargo recruitment with the recruitment of molecular tethers and targeting/fusion determinants. We will determine the structural organization of the tether p115 using x-ray crystallography. We will explore the contribution of Sec13/31 to the completion of budding and fission of COPII vesicles from the ER through biochemical, molecular and structural analyses, allowing us to test different models for COPII coat polymerization. The proposed studies should allow us to develop significant mechanistic insight into the crucial early events in the secretory pathway that control the flow of nearly one-third of genome into the cell.

描述（由申请人提供）：我们的远距离目标是了解膜结合和胞质蛋白的作用，这些蛋白将货物的分类从哺乳动物细胞的内质网（ER）发芽。在出口期间选择和集中货物的机制尚不清楚。为了解决这一目标，我们将重点关注SAR1 GTPase及其上游和下游效应子在货物选择中的核心作用。 AIM I. SAR1激活的分子基础导致过渡元件形成。我们将检查SARL通过与哺乳动物Sec12鸟嘌呤核苷酸交换因子（GEF）相互作用来指导出口位点组装的机制，以生成使用KIF依赖性过程形成的管状元件。具体目标II。货物选择的生化基础。我们将探讨以下假设：前萌芽复合物的新成分是蛋白质机器的一部分，该蛋白质机器将货物选择与ER功能的其他方面进行协调，以将货物选择为Copii囊泡。我们将解决货物识别，SEC23/24募集和涂层聚合的分子基础，并生成转基因小鼠模型以追求哺乳动物Sec24（A-D）同工型的独特功能。特定的目标生病。囊泡成熟。我们将探讨与募集分子系和靶向/融合决定因素协调货物招募的基础。我们将使用X射线晶体学确定系绳P115的结构组织。我们将探讨SEC13/31对从ER到生化，分子和结构分析的培养基囊泡完成和裂变的贡献，从而使我们能够测试不同模型的COPII涂层聚合。拟议的研究应使我们能够对分泌途径中关键的早期事件进行重大的机械洞察力，从而控制了将近三分之一的基因组流入细胞的流动。