Accurate Molecular Decision Making during Protein Biogenesis

蛋白质生物合成过程中准确的分子决策

• 批准号: 10372995
• 负责人: Shu-ou Shan
• 金额: $ 97.03万
• 依托单位: CALIFORNIA INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-04-01 至 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10372995
• 关键词: ATP phosphohydrolase; Bacteria; Biochemical; Biogenesis; Biophysical Process; Biophysics; Cells; Client; Crowding; Decision Making; Disease; Ensure; Environment; Enzymes; Eukaryotic Cell; Excision; Generations; Goals; Grant; Individual; Investigation; Knowledge; Maintenance; Mediating; Membrane; Membrane Proteins; Methionine; Modeling; Molecular; Molecular Chaperones; N-terminal; Pathology; Pathway interactions; Physiology; Plant Roots; Process; Proteins; Proteome; Reagent; Regulation; Research; Resolution; Ribosomes; Signal Recognition Particle; System; Tail; Time; Translations; Triage; design; experimental study; in vivo; insight; prevent; programs; proteostasis; spatiotemporal; targeted delivery; tool

Project Summary: Accurate Molecular Decision Making during Protein Biogenesis Accurate protein biogenesis is essential for the generation and maintenance of a functional proteome. Our long term goal is to understand the molecular mechanisms by which diverse protein biogenesis pathways in the cell accurately select nascent protein substrates and ensure their correct folding, localization, and maturation. Two major components define our research program in this grant cycle. First, we will use a combination of biochemical, biophysical, and in vivo experiments to decipher the mechanisms by which nascent proteins emerging from the ribosome are selected and processed by ribosome-associated protein biogenesis factors (RPBs) in the crowded space of the ribosome tunnel exit. These studies will include a new co-translational membrane protein targeting pathway mediated by SecA, enzymes mediating N-terminal methionine excision on nascent proteins in bacteria, and co-translational protein targeting mediated by SRP in the mammalian system. In addition to studying the biochemical and biophysical mechanisms of the individual protein biogenesis pathways, we will also elucidate how each of these factors coordinates with other RPBs in space and time during ongoing translation, and how this coordination reshapes the efficiency and fidelity of the individual pathways. Second, we will decipher the mechanisms by which aggregation-prone membrane proteins are effectively protected and facilely guided to the target membrane during their post-translational targeting. These studies will use two membrane protein biogenesis pathways as models: (i) an ATP-independent chaperone cpSRP43, which allows us to decipher, at biophysical resolution, the molecular mechanisms by which a small chaperone effectively protects multi-pass membrane protein clients and achieves spatiotemporal regulation of its client interactions in the absence of ATPase cycles or cochaperones; (ii) the guided-entry of tail-anchored proteins (GET) pathway, which provides an excellent system to decipher how a multi-component Hsp70- cochaperone cascade protects, funnels, and triages nascent membrane proteins during their targeted delivery. Investigation of the GET pathway will also allow us to gain insights into the design and organizational principles of analogous chaperone networks in the cell. The proposed experiments will not only generate high resolution understandings of the individual protein biogenesis pathways, but also establish valuable tools, reagents to explore the action of other protein biogenesis machineries. Most importantly, this research will generate important conceptual frameworks to understand how nascent proteins are accurately selected into their appropriate biogenesis pathways in the crowded cytosolic environment.

项目摘要：蛋白质生物合成过程中准确的分子决策 准确的蛋白质生物发生对于功能性蛋白质的产生和维持至关重要 蛋白质组。我们的长期目标是了解不同的分子机制 细胞中的蛋白质生物发生途径准确选择新生蛋白质底物并确保 它们的正确折叠、定位和成熟。我们的研究有两个主要组成部分 本拨款周期中的计划。 首先，我们将结合生物化学、生物物理和体内实验来破译 选择从核糖体中出现的新生蛋白质的机制 由核糖体相关蛋白生物发生因子（RPB）在拥挤的空间中加工 核糖体隧道出口。这些研究将包括一种新的共翻译膜蛋白 SecA介导的靶向途径，介导N末端甲硫氨酸切除的酶 细菌中的新生蛋白，以及 SRP 介导的共翻译蛋白靶向 哺乳动物系统。除了研究其生化和生物物理机制外 个体蛋白质生物发生途径，我们还将阐明每个因素如何 在正在进行的翻译过程中与其他 RPB 在空间和时间上进行协调，以及如何协调 协调重塑了各个路径的效率和保真度。 其次，我们将破译易于聚集的膜蛋白的机制 在翻译后过程中得到有效保护并轻松引导至目标膜 瞄准。这些研究将使用两种膜蛋白生物发生途径作为模型：（i） ATP 独立伴侣 cpSRP43，它使我们能够以生物物理分辨率破译， 小伴侣有效保护多通道的分子机制 膜蛋白客户并实现其客户相互作用的时空调节 缺乏 ATP 酶循环或辅助伴侣； (ii) 尾部锚定蛋白的引导进入（GET） 途径，它提供了一个出色的系统来破译多组分 Hsp70- 辅伴侣级联在新生膜蛋白的过程中保护、漏斗和分类 有针对性的交付。对 GET 途径的研究也将使我们能够深入了解 细胞中类似伴侣网络的设计和组织原则。 所提出的实验不仅将产生对 单个蛋白质的生物发生途径，同时还建立了有价值的工具、试剂来探索 其他蛋白质生物发生机制的作用。最重要的是，这项研究将产生 了解如何准确选择新生蛋白质的重要​​概念框架 在拥挤的细胞质环境中进入适当的生物发生途径。