Quality Control of Membrane Proteins

膜蛋白的质量控制

基本信息

批准号：
9147473
负责人：
Sanjay B Hari
金额：
$ 5.8万
依托单位：
MASSACHUSETTS INSTITUTE OF TECHNOLOGY
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-09-01 至 2017-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9147473
关键词：
ATP phosphohydrolase ATP-Dependent Proteases Address Affect Bacteria Bacterial Infections Biochemical Biological Sciences C-terminal Cell physiology Cells Complex Data Dissociation Effectiveness Ensure Environment Event Genome Goals Health Human In Vitro Kinetics Label Lead Left Lipid Bilayers Location Measures Membrane Membrane Proteins Messenger RNA Methods Normal Cell Organism Peptide Hydrolases Physiological Predisposition Property Protein Fragment Proteins Proteomics Quality Control Ribosomes Role Source System Testing Thermodynamics Training Transcript Translations Work career combat cytotoxicity feeding fighting insight new therapeutic target polypeptide prevent protein degradation public health relevance research study response therapeutic development tmRNA

ATP phosphohydrolase ATP-Dependent Proteases Address Affect Bacteria Bacterial Infections Biochemical Biological Sciences C-terminal Cell physiology Cells Complex Data Dissociation Effectiveness Ensure Environment Event Genome Goals Health Human In Vitro Kinetics Label Lead Left Lipid Bilayers Location Measures Membrane Membrane Proteins Messenger RNA Methods Normal Cell Organism Peptide Hydrolases Physiological Predisposition Property Protein Fragment Proteins Proteomics Quality Control Ribosomes Role Source System Testing Thermodynamics Training Transcript Translations Work career combat cytotoxicity feeding fighting insight new therapeutic target polypeptide prevent protein degradation public health relevance research study response therapeutic development tmRNA

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项目摘要

DESCRIPTION (provided by applicant): Intracellular quality control mechanisms prevent misregulation and cytotoxicity. Protein degradation systems maintain protein quality by destroying potentially harmful incomplete or faulty polypeptides. Unfinished protein fragments are often the products of ribosomes that stall on mRNA transcripts. Ribosomal stalling also prevents normal termination and mRNA dissociation, thereby depleting the pool of ribosomes available for translation. In bacteria, a mechanism known as tmRNA rescue frees stalled ribosomes and marks incomplete proteins for destruction. Although this system has been studied in depth within the context of cytosolic proteins, relatively little is known about its effectiveness towards membrane proteins. Given that a significant portion of genomes of both simple and complex organisms encode membrane proteins, it is important to understand how stalling events of this type are handled and how protein quality control mechanisms operate in the challenging environment of the membrane interface. The overall goal of this project is to study the physiological response to ribosomes stalled during the synthesis of membrane proteins. Experiments conducted directly in bacteria will seek to understand the role of the tmRNA system in labeling incomplete membrane proteins for destruction as well as the role of specific proteases in degrading these proteins. The effect of membrane protein topology on degradation will also be ascertained. Next, quantitative proteomic methods will be used to determine the extent of endogenous membrane protein labeling by the tmRNA system and which of these proteins are degraded by proteases. Finally, an in vitro system will be developed to examine mechanistically the degradation of membrane proteins by different ATP-dependent proteases. It is expected that these experiments will yield a more comprehensive view of protein quality control in cells. A better understanding of protein quality control in bacteria could lead o the discovery of new targets for therapeutic development to combat bacterial infections.

描述（通过应用程序提供）：细胞内质量控制机制可防止正调和细胞毒性。蛋白质降解系统通过破坏潜在有害的不完全或故障多肽来保持蛋白质质量。未完成的蛋白质片段通常是停滞在mRNA转录本上的核糖体产物。核糖体失速还可以防止正常的终止和mRNA解离，从而耗尽可用于翻译的核糖体。在细菌中，一种称为TMRNA的机制挽救了释放的核糖体和标记不完全破坏的蛋白质。尽管该系统在胞质蛋白的背景下进行了深入研究，但对其对膜蛋白的有效性的了解相对较少。鉴于简单和复杂生物的很大一部分基因组编码膜蛋白，因此重要的是要了解如何处理这种停滞事件以及蛋白质质量控制机制如何在膜界面的挑战环境中起作用。该项目的总体目标是研究膜蛋白合成过程中停滞的核糖体的物理反应。直接在细菌中进行的实验将寻求了解TMRNA系统在标记不完整的膜蛋白上为破坏以及特定蛋白在降解这些蛋白质中的作用的作用。还将确定膜蛋白拓扑对降解的影响。接下来，将使用定量蛋白质方法来确定TMRNA系统的内源性膜蛋白标记的程度，以及这些蛋白质中的哪种被蛋白质降解。最后，将开发一个体外系统，以通过不同的ATP依赖性蛋白机械地检查膜蛋白的降解。预计这些实验将对细胞中的蛋白质质量控制产生更全面的看法。对细菌中蛋白质质量控制的更好理解可能会导致发现新的靶标的治疗性发育靶标，以打击细菌感染。