Quality Control Mechanisms in Protein Synthesis

蛋白质合成中的质量控制机制

• 批准号: 10707986
• 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/10707986
• 关键词: Adaptor Signaling Protein; Antibiotic Therapy; Antibiotics; Bacteria; Binding Sites; Biochemical; Biogenesis; C-terminal; Crowding; Cytoplasm; Data; Defect; Development; Enzymes; Eukaryota; Exoribonucleases; Family; Future; Genetic; 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; cofactor; 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.

项目摘要 该研究项目的目的是获得对跨翻译的更深入的理解，这是一种保守的细菌系统 翻译质量控制，定向蛋白水解和不间断的mRNA衰变。我们拟议的研究的基本前提 是SMPB-TMRNA介导的跨翻译过程解决了由不间断mRNA引起的所有问题，包括 营救和回收非生产性的核糖体，潜在有毒的新生多肽的蛋白水解以及 因果缺陷mRNA的选择性衰变。我们建议TMRNA反应的核糖体充当招募的枢纽 专门的救援因素和相互连接的打捞途径的启动。因此，在接下来的五年中，我们将 解决反译过程的两个独立方面：（1）TMRNA标记蛋白的衔接子引导的蛋白水解 （2）tmRNA-辅助的不间动mRNA衰变。在目标I中，我们将调查翻译机械是否充当 通过募集AAA+ CLPXP蛋白酶系统转化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型的底物识别机制，该机制可以通过其蛋白酶促进CLPXP蛋白酶 特异性增强因子SSPB，以捕获其在核糖体生物发生部位的明显蛋白质。详细的知识 关于如何通过这种新颖的途径捕获特定底物的方式将为AAA+酶的新灯提供明显的新灯光 旨在定义细胞位置以及蛋白酶在不良条件下如何促进细胞适应性和存活。在 AIM II，我们将研究TMRNA介导的核糖体救援系统与选择性捕获和 RNase R的mRNA有缺陷的衰减。我们希望阐明将RNase R募集到翻译的机制 机械并定义其确切的结合位点，并在救出的核糖体上进行互动。我们将探索可能性 核糖体成分的独特修饰会产生专门的核糖体，在招募RNase R中起关键作用 到TMRNA反应的核糖体。最近的研究提供了令人信服的证据，以证明跨翻译 过程，CLPXP和LON蛋白酶是几种致病细菌的各种调节途径的关键参与者，并且 因此是发病机理所必需的。该项目提出的遗传，生化和结构研究提供了 独特的机会来获得对跨翻译过程的重大新见解，并确定未来的新目标 开发新的抗生素。