Regulation by Proteolysis-Independent Ubiquitination

不依赖蛋白水解的泛素化调节

• 批准号: 8511689
• 负责人: Peter Kaiser
• 金额: $ 30.1万
• 依托单位: UNIVERSITY OF CALIFORNIA-IRVINE
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-08-01 至 2016-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8511689
• 关键词: 26S proteasome; Address; Affect; Binding; Biochemical Genetics; Biochemistry; Biological; Biomedical Research; Cell Cycle; Cell Cycle Regulation; Cell physiology; Cells; Chromatin Structure; Complex; Cullin Proteins; DNA Repair; Degradation Pathway; Diagnostic; Disease; Dissection; Drug Targeting; Elements; Enzymes; Funding; Genetic Transcription; Grant; Growth; Health; Human; Infection; Knowledge; Label; Left; Life; Ligase; Link; Lysine; Malignant Neoplasms; Mediating; Metabolic stress; Modeling; Modification; Molecular; Nerve Degeneration; Pathway interactions; Physiology; Play; Polyubiquitin; Post-Translational Protein Processing; Process; Proteasome Inhibitor; Proteins; Proteolysis; Regulation; Regulation of Proteolysis; Repression; Research; Role; SKP Cullin F-Box Protein Ligases; Signal Pathway; Signal Transduction; System; Trans-Activators; Ubiquitin; Ubiquitination; Yeasts; chaperonin; design; drug discovery; human disease; inhibitor/antagonist; innovation; insight; interest; multicatalytic endopeptidase complex; novel; protein complex; protein degradation; protein function; research and development; research study; therapeutic target; tool; transcription factor; transmission process; treatment strategy; ubiquitin ligase; ubiquitin-protein ligase

DESCRIPTION (provided by applicant): Ubiquitylation, the covalent attachment of the small protein ubiquitin to other proteins, regulates a host of cellular processes. Protein ubiquitylation has become a synonym for protein degradation, and most of the current research is focused on the role of ubiquitin in targeting proteins for degradation by the 26S proteasome. However, we are beginning to appreciate that a number of proteins are regulated by ubiquitylation in a proteolysis-independent manner. Recent system-wide experiments suggest that only little more than fifty percent of ubiquitylated proteins are efficiently degraded by the proteasome, implying that protein ubiquitylation has widespread signaling functions outside the proteasome pathway. Molecular understanding of these proteolysis-independent ubiquitin signals will be important for basic biomedical research and development of therapeutics targeting the ubiquitin system. Some of the key questions are: Why are some ubiquitylated proteins degraded and others are not? How can ubiquitylation directly affect protein activity? What are the mechanisms of direct protein regulation by ubiquitylation and what are the components mediating regulation? We analyze a system regulated by the cullin-RING ubiquitin ligase complex SCFMet30, which connects metabolic stress to cell cycle regulation. This pathway is particularly suited to probe non-proteolytic signals of ubiquitylation because the same ligase modifies different substrate proteins with the same lysine-48 linked ubiquitin chain, yet some substrates are labeled for degradation while other substrates are regulated in a proteolysis-independent manner. This proposal builds on a plethora of tools available to analyze biochemistry and physiology of this pathway and will address (i) how regulated ubiquitin-binding domains can dictate signal identity and switch between ubiquitin chains signaling for degradation and non-proteolytic regulation (Aim 1); (ii) how a polyubiquitin chain can directly regulate transcription factor activity (Aim 2) and (iii) how ubiquitylation induces active disassembly/remodeling of multisubunit protein complexes to modulate their activities (Aim 3). Ubiquitylation affects many important cellular processes and has been linked to a number of human diseases including cancer, neurodegeneration, and retroviral infection. A contribution of proteolysis-independent ubiquitylation in these diseases is emerging and it will be important to understand the mechanism behind this regulation to design diagnostic tools and treatment strategies. This proposal aims to achieve detailed mechanistic insight into proteolysis-independent ubiquitin signals and to define the concepts of these regulatory ubiquitylation pathways.

描述（由申请人提供）：泛素化，即小蛋白泛素与其他蛋白质的共价连接，调节宿主的细胞过程。蛋白质泛素化 泛素已成为蛋白质降解的代名词，目前大部分研究都集中在泛素在 26S 蛋白酶体降解蛋白质中的作用。然而，我们开始认识到许多蛋白质以不依赖于蛋白水解的方式受到泛素化的调节。最近的全系统实验表明，只有百分之五十多一点的泛素化蛋白质能够被蛋白酶体有效降解，这意味着蛋白质泛素化在蛋白酶体途径之外具有广泛的信号传导功能。对这些不依赖于蛋白水解的泛素信号的分子理解对于基础生物医学研究和针对泛素系统的疗法的开发非常重要。一些关键问题是：为什么一些泛素化蛋白质会被降解，而另一些则不会？泛素化如何直接影响蛋白质活性？通过泛素化直接调节蛋白质的机制是什么？介导调节的成分是什么？ 我们分析了由 cullin-RING 泛素连接酶复合物 SCFMet30 调节的系统，该系统将代谢应激与细胞周期调节联系起来。该途径特别适合探测泛素化的非蛋白水解信号，因为相同的连接酶用相同的赖氨酸 48 连接的泛素链修饰不同的底物蛋白，但一些底物被标记为降解，而其他底物以不依赖于蛋白水解的方式进行调节。该提案建立在大量可用于分析该途径的生物化学和生理学的工具的基础上，并将解决（i）受调节的泛素结合域如何决定信号身份以及泛素链信号降解和非蛋白水解调节之间的切换（目标1）； (ii) 多聚泛素链如何直接调节转录因子活性（目标 2）以及 (iii) 泛素化如何诱导多亚基蛋白复合物主动分解/重塑以调节其活性（目标 3）。 泛素化影响许多重要的细胞过程，并与许多人类疾病有关，包括癌症、神经变性和逆转录病毒感染。不依赖蛋白水解的泛素化在这些疾病中的作用正在显现，了解这种调节背后的机制对于设计诊断工具和治疗策略非常重要。该提案旨在实现对不依赖蛋白水解的泛素信号的详细机制洞察，并定义这些调节泛素化途径的概念。