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: 10399615
• 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/10399615
• 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 在三个主要的细胞内贩运途径中 - 内吞作用和自噬 - 蛋白质以及 膜分别分泌，内部化或穿梭以降解。这些途径受调节 通过核苷酸交换激活（GEF）的配置的YPT/RAB GTPase，招募它们 对膜的影响。这些效果是介质囊泡运输步骤的机械组件， 从地点形成，到运动和靶向到融合。自从YPT/RAB领域工作以来 成立并促进了基于其行动方式的原则公式。这些包括想法 它们在包含GEF/s的“ GTPase模块”中发挥作用 或台阶特异性膜微区。虽然目前已知YPT/RAB功能的机制，但 有关途径和步骤协调的问题仍然开放。我们建议YPT/RAB GTPASE 协调三个级别的细胞内贩运：多个途径的协调，运输的整合 进入整个途径，并协调单个运输步骤的囊泡运输子位。 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较小的蛋白质组，这对于探索很重要 以下协调问题：多个途径协调：我建议YPT/RABS协调 在两个交叉口的分泌和内吞作用的自噬。首先，YPT1/RAB1是必需的 在两个不同的GTPase模块的背景下，分泌和自噬的开始。在第二个 相交，内吞作用的合并和自噬晚期由共享的VPS21/RAB5 GTPase调节 模块。在这里，我们将确定单元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种优先级。运输步骤的整合：在这里，我们将讨论两个主要 问题：首先，YPTS如何调节途径的开始，尤其是在单个GTPase功能时 在两个不同的模块的背景下？第二，YPTS坐标的特定机制是什么 分泌和自噬的早期和晚期？囊泡运输子步骤的协调：我们将探索 分泌和自噬途径的最新步骤，该途径已知GTPase模块的成员， 并询问该功能如何顺序募集。我们将使用经典和分子遗传学 结合细胞生物学和生物化学方法来解决这些问题。 有效且协调良好的细胞运输途径网络对于所有系统的所有系统都很重要 人体，甚至较小的缺陷都会导致严重的疾病。 YPT/Rabs通常与 获得和遗传疾病的范围，我们研究的疾病与癌症和 神经变性。最后，我们最近展示了酵母建模在理解如何 保守的蛋白质变异会引起神经发育障碍。