Coordination of intracellular trafficking pathways by Ypt/Rab GTPases and their GEFs.

Ypt/Rab GTPases 及其 GEF 协调细胞内运输途径。

• 批准号: 10615724
• 负责人: Nava Segev
• 金额: $ 39.98万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-05-01 至 2026-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10615724
• 关键词: Address; Autophagocytosis; Biochemistry; Biological Models; Cells; Cellular biology; Defect; Disease; Endocytosis; Exocytosis; Formulation; Growth; Guanosine Triphosphate Phosphohydrolases; Hereditary Disease; Human body; Individual; Malignant Neoplasms; Mediating; Membrane; Membrane Microdomains; Minor; Molecular; Molecular Genetics; Monomeric GTP-Binding Proteins; Nerve Degeneration; Neurodevelopmental Disorder; Nucleotides; Pathway interactions; Proteins; Proteome; Research; Stress; System; Variant; Vesicle; Work; Yeast Model System; Yeasts; cell motility; member; rab GTP-Binding Proteins; recruit; trafficking; vesicle transport

Abstract In the three major intracellular trafficking pathways–exocytosis, endocytosis and autophagy–proteins and membranes are secreted, internalized or shuttled for degradation, respectively. These pathways are regulated by the conserved Ypt/Rab GTPases that when activated by nucleotide exchangers (GEFs), recruit their effectors to membranes. These effectors are machinery components that mediate vesicular transport steps, from vesicle formation, through motility and targeting, to fusion. I have worked in the Ypt/Rab field since its inception and contributed to the formulation of principles that underlie their mode of action. These include ideas that they function in “GTPase modules”, which contain GEF/s, a GTPase, and effector/s, to organize pathway- or step-specific membrane microdomains. While mechanisms underlying Ypt/Rab function are currently known, questions regarding pathway and step coordination remain open. We propose that Ypt/Rab GTPases coordinate intracellular trafficking at three levels: Coordination of multiple pathways, integration of transport steps into whole pathways, and coordination of vesicular transport sub-steps of individual transport steps. The proposed research relies on our recent findings using yeast as a model system, and we will continue using yeast due to its smaller proteome that results in a much smaller interactome, which is important for exploring the following coordination issues: Multiple pathways coordination: I propose that Ypt/Rabs coordinate autophagy with secretion and endocytosis at two intersections. In the first, Ypt1/Rab1 is required for the beginning of secretion and autophagy in the context of two different GTPase modules. In the second intersection, merging of endocytosis and late autophagy is regulated by a shared Vps21/Rab5 GTPase module. Here, we will determine whether cells prioritize certain pathways under different environmental conditions and how such a priority is promoted. Integration of transport steps: Here, we will address two major questions: First, how do Ypts regulate the beginning of a pathway, especially when a single GTPase functions in the context of two different modules? Second, what are the specific mechanisms by which Ypts coordinate early and late steps in secretion and autophagy? Coordination of vesicular transport sub-steps: We will explore late steps of the secretory and autophagy pathways, for which members of the GTPase modules are known, and ask how effectors that function sequentially are recruited. We will use classical and molecular genetics combined with cell biology and biochemistry approaches to address these questions. An efficient and well-coordinated network of cellular trafficking pathways is important for all the systems of the human body, and even a minor defect can result in a severe disease. Ypt/Rabs in general were implicated in a spectrum of acquired and inherited diseases, and those we study were associated with cancer and neurodegeneration. Finally, we recently showed the value of yeast modeling in understanding how a conserved protein variant causes a neurodevelopmental disorder.

摘要 在胞吐、胞内和自噬这三条主要的细胞内运输途径中，蛋白质和 膜分别被分泌、内化或穿梭以进行降解。这些途径是受调控的 通过保守的YPT/Rab GTP酶，当被核苷酸交换器(GEF)激活时，招募他们的 膜的效应器。这些效应器是调节囊泡运输步骤的机械部件， 从囊泡形成，到运动和靶向，再到融合。我一直在YPT/RAB油田工作，因为它 在这方面，联合国儿童基金会发起了行动计划，并为制定其行动模式所依据的原则作出了贡献。这些想法包括 它们在“GTP酶模块”中发挥功能，其中包括全球环境基金/S、GTP酶和效应器/S，以组织途径- 或步骤特异的膜微域。虽然YPT/RAB功能的潜在机制目前是已知的， 有关路径和步骤协调的问题仍然悬而未决。我们提出YPT/Rab GTP酶 在三个层面上协调细胞内运输：多条路径的协调，运输的整合 步入整个路径，并协调各个运输步骤中的囊泡运输子步骤。 拟议的研究依赖于我们使用酵母作为模型系统的最新发现，我们将继续使用 酵母由于其较小的蛋白质组导致了更小的相互作用组，这对探索很重要 以下协调问题：多途径协调：我建议青瓦台/拉布斯协调 在两个交叉点有分泌和内吞的自噬。在第一个代码中，Ypt1/Rab1是 在两个不同的GTPase模块的背景下，开始分泌和自噬。在第二个 内吞和晚期自噬的交叉、合并受共享的Vps21/Rab5 GTP酶调控 模块。在这里，我们将确定细胞是否在不同的环境下优先选择某些路径 条件以及如何促进这一优先事项。运输步骤的整合：在这里，我们将解决两个主要问题 问题：首先，YPTS如何调节通路的开始，特别是当单个GTP酶发挥作用时 在两个不同模块的背景下？第二，YPTS协调的具体机制是什么？ 分泌物和自噬的早期和晚期？协调囊泡运输的子步骤：我们将探索 已知GTPase模块成员的分泌和自噬途径的后期步骤， 并询问如何招募按顺序发挥作用的效应器。我们将使用经典遗传学和分子遗传学 结合细胞生物学和生物化学的方法来解决这些问题。 一个高效和协调良好的细胞运输路径网络对所有系统都很重要 即使是微小的缺陷也可能导致严重的疾病。YPT/RABS总体上涉及一项 获得性和遗传性疾病的谱系，以及我们研究的那些与癌症和 神经退行性变。最后，我们最近展示了酵母建模的价值，它有助于理解 保守的蛋白质变异会导致神经发育障碍。