Quality Control Mechanisms in Protein Synthesis

蛋白质合成中的质量控制机制

• 批准号: 10444816
• 负责人: A. WALI KARZAI
• 金额: $ 39.31万
• 依托单位: STATE UNIVERSITY NEW YORK STONY BROOK
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-21 至 2026-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10444816
• 关键词: Adaptor Signaling Protein; Address; Antibiotic Therapy; Antibiotics; Bacteria; Binding Sites; Biochemical; Biogenesis; C-terminal; Crowding; Data; Defect; Development; Enzymes; Eukaryota; Exoribonucleases; Family; Future; Genetic; Glutamates; Goals; Knowledge; Light; Link; Location; Measures; Mediating; Messenger RNA; Modeling; Modification; Molecular; Multiple Bacterial Drug Resistance; Participant; Pathogenesis; Pathway interactions; Peptide Hydrolases; Play; Positioning Attribute; Process; Protein Biosynthesis; Proteins; Proteolysis; Quality Control; RNA; Recycling; Regulatory Pathway; Research Project Grants; Ribonucleases; Ribosomal Protein S6; Ribosomes; Role; Site; Specificity; System; Testing; Transcript; Translating; Translation Process; Translations; Virulence; design; endopeptidase La; enhancing factor; fitness; improved; insight; mRNA Decay; member; novel; pathogenic bacteria; polyglutamate; polypeptide; recruit; ribonuclease R; tmRNA

Project Summary The goal of this research project is to gain deeper mechanistic insights into trans-translation, a conserved bacterial system for translation quality control, directed proteolysis, and nonstop mRNA decay. The fundamental premise of our proposed studies is that the SmpB-tmRNA mediated trans-translation process solves all of problems caused by nonstop mRNAs, including rescue and recycling of unproductively stalled ribosomes, proteolysis of the potentially toxic nascent polypeptides, and selective decay of the causative defect mRNA. We propose that the tmRNA-rescued ribosome serves as a hub for recruitment of specialized rescue factors and initiation of interconnected salvage pathways. Therefore, over the next five years we will address two independent aspects of the trans-translation process: (1) adaptor guided proteolysis of tmRNA tagged proteins and (2) tmRNA-facilitated nonstop mRNA decay. In Aim I, we will investigate whether the translation machinery serves as a platform for initiating guided proteolysis by recruiting the AAA+ ClpXP protease system to translating ribosomes. The primary aim of our studies is to investigate a novel substrate recognition mechanism that enables the ClpXP protease, via its specific-enhancing factor SspB, to capture marked proteins at their site of biogenesis on the ribosome. A detailed knowledge of how specific substrate are captured via this novel pathway will shed significant new light on how AAA+ enzymes are directed to define cellular locations and how proteases contribute to cellular fitness and survival under adverse conditions. In Aim II, we will investigate the link between the tmRNA-mediated ribosome rescue system and the selective capture and decay of defective mRNAs by RNase R. We wish to elucidate the mechanism by which RNase R is recruited to the translation machinery and define its exact binding site and interacting partners on the rescued ribosome. We will explore the possibility that a unique modification of ribosomal components creates specialized ribosomes that play a key role in recruiting RNase R to tmRNA-rescued ribosomes. Recent studies have provided compelling evidence to demonstrate that the trans-translation process and ClpXP and Lon proteases are key participants in various regulatory pathways in several pathogenic bacteria, and therefore are required for pathogenesis. The genetic, biochemical, and structural studies proposed in this project offer the unique opportunity to gain significant new insights into the trans-translation process and identify new targets for future development of new antibiotics.

项目概要 该研究项目的目标是获得对反式翻译（一种保守的细菌系统）更深入的机制见解。 翻译质量控制、定向蛋白水解和不间断 mRNA 衰减。我们提出的研究的基本前提 SmpB-tmRNA 介导的反式翻译过程解决了由不间断 mRNA 引起的所有问题，包括 拯救和回收无效停滞的核糖体，潜在有毒的新生多肽的蛋白水解，以及 致病缺陷 mRNA 的选择性衰变。我们建议 tmRNA 拯救核糖体作为招募中心 专门的救援因素和相互关联的救援路径的启动。因此，未来五年我们将 解决反式翻译过程的两个独立方面：(1) 接头引导的 tmRNA 标记蛋白的蛋白水解 (2) tmRNA 促进 mRNA 不间断衰减。在目标 I 中，我们将研究翻译机器是否充当 通过招募 AAA+ ClpXP 蛋白酶系统来翻译核糖体来启动引导蛋白水解的平台。这 我们研究的主要目的是研究一种新的底物识别机制，该机制通过其 特异性增强因子 SspB，用于捕获核糖体上生物发生位点的标记蛋白质。详细的知识 特定底物如何通过这一新途径被捕获的研究将为 AAA+ 酶如何发挥作用提供重要的新线索 旨在确定细胞位置以及蛋白酶如何促进细胞在不利条件下的适应性和生存。在 目标 II，我们将研究 tmRNA 介导的核糖体救援系统与选择性捕获和选择性捕获之间的联系 RNase R 降解有缺陷的 mRNA。我们希望阐明 RNase R 被招募到翻译中的机制 机器并定义其精确的结合位点和在被拯救的核糖体上相互作用的伙伴。我们将探索可能性 核糖体成分的独特修饰产生了专门的核糖体，在招募 RNase R 方面发挥着关键作用 tmRNA 拯救核糖体。最近的研究提供了令人信服的证据来证明转译 过程以及 ClpXP 和 Lon 蛋白酶是多种病原菌各种调节途径的关键参与者，并且 因此是发病机制所必需的。该项目中提出的遗传、生化和结构研究提供了 获得对翻译过程的重要新见解并确定未来新目标的独特机会 新抗生素的开发。