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: 10704918
• 负责人: Nava Segev
• 金额: $ 2.56万
• 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/10704918
• 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.

抽象的 在三种主要的细胞内运输途径——胞吐作用、内吞作用和自噬作用中——蛋白质和 膜分别被分泌、内化或穿梭降解。 由保守的 Ypt/Rab GTPases 驱动，当被核苷酸交换器 (GEF) 激活时，它们会招募其 这些效应器是介导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 领域工作。 并为制定其行动模式所依据的原则做出了贡献。 它们在“GTP酶模块”中发挥作用，其中包含GEF、GTP酶和效应器，以组织通路- 或步骤特异性膜微结构域虽然目前已知 Ypt/Rab 功能的机制， 关于途径和步骤协调的问题仍然悬而未决，我们建议 Ypt/Rab GTPases。 在三个层面上协调细胞内运输：多种途径的协调、运输的整合 步骤进入整个路径，并协调各个运输步骤的囊泡运输子步骤。 拟议的研究依赖于我们最近使用酵母作为模型系统的发现，我们将继续使用 酵母由于其较小的蛋白质组而导致相互作用组更小，这对于探索非常重要 以下协调问题： 多途径协调：我建议 Ypt/Rabs 协调 在两个交叉点处具有分泌和内吞作用的自噬在第一个中需要 Ypt1/Rab1。 在两个不同的 GTP 酶模块的背景下开始分泌和自噬。 内吞作用和晚期自噬的交叉、合并由共享的 Vps21/Rab5 GTPase 调节 在这里，我们将确定细胞在不同环境下是否优先考虑某些途径。 条件以及如何促进这一优先事项的运输步骤的整合：在这里，我们将讨论两个主要问题。 问题：首先，Ypts 如何调节通路的开始，特别是当单个 GTPase 发挥作用时 其次，Ypts 协调的具体机制是什么？ 分泌和自噬的早期和晚期步骤？协调囊泡运输子步骤：我们将探讨 分泌和自噬途径的后期步骤，其中 GTPase 模块的成员是已知的， 并询问如何招募依次起作用的效应器。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方法来解决这些问题。 高效且协调良好的细胞运输途径网络对于所有系统都很重要 人体，即使是轻微的缺陷也可能导致严重的疾病。 一系列获得性和遗传性疾病，我们研究的疾病与癌症和 最后，我们最近展示了酵母建模在理解神经变性如何发生方面的价值。 保守的蛋白质变异会导致神经发育障碍。