Functions of Ub-like Proteins & Processing Proteases

Ub 样蛋白的功能

• 批准号: 6521874
• 负责人: KEITH D WILKINSON
• 金额: $ 30.35万
• 依托单位: EMORY UNIVERSITY
• 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 2006-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6521874
• 关键词: chemical conjugate; chemical synthesis; endopeptidases; enzyme mechanism; enzyme substrate; protease inhibitor; protein structure function; proteomics; ubiquitin

DESCRIPTION (provided by applicant): Deubiquitinating enzymes (DUBs, also known as deconjugating enzymes) are important regulatory proteases that process the primary gene products of the ubiquitin gene family, reverse the conjugation of ubiquitin to cellular proteins, and disassemble the polyubiquitin chains that target proteins for degradation by the proteasome. As such, they regulate proteolysis and thereby progression through the cell cycle, signal transduction pathways, the stress response, antigen presentation, chromatin structure, receptor internalization and endocytosis. It has only recently been appreciated that modification of proteins by other ubiquitin-like (Ubl) proteins exerts a similar targeting function. The underlying assumption of this grant is that regulation of the Ubl pathways by deconjugation of ubiquitin-like proteins is likely to be equally important, with roles in cancer, the regulation of growth and apoptosis. The enzymes that reverse the conjugation of UbI proteins (Ubiquitin-like protein proteases, ULP) are attractive targets for further study since the reversal of these modifications is expected to interfere with functions. As they are proteases, a large body of work suggests approaches to effective pharmacological intervention. Additionally, it is easier (conceptually and practically) to interfere with these pathways by overexpressing a deconjugating enzyme than it is to prevent attachment of the UbI domain; an approach that requires gene knock-out or dominant negative approaches. Understanding the role of these deconjugating enzymes requires that we know more about this class of enzymes, their substrates and their regulation. A series of inhibitors and substrates for ULPs will be synthesized and used to test three specific hypotheses. First, Dr. Wilkinson will test the hypothesis that an integral subunit of the mammalian COP9-signalosome is able to reverse the Nedd8 modification of cullins. He also will test the hypothesis that modification of proteins by ISG15 are an integral part of the interferon response by identifying, and interfering with the function of, enzymes which reverse this modification. He will determine if conjugation of the proapoptotic Ubl FAT10 is reversible. Finally, he will test the hypothesis that HAUSP and/or SENPI are the Ubl that removes SUMO-1 from the Promyelocytic leukemia protein, triggering the disassembly of PML.

描述（由申请人提供）：去泛素化酶（DUB，也称为去缀合酶）是重要的调节性蛋白酶，其加工泛素基因家族的初级基因产物，逆转泛素与细胞蛋白的缀合，并分解靶向蛋白质的聚泛素链以供蛋白酶体降解。因此，它们调节蛋白水解，从而通过细胞周期、信号转导途径、应激反应、抗原呈递、染色质结构、受体内化和内吞作用进行。直到最近才认识到，其他泛素样蛋白（Ubl）对蛋白质的修饰发挥了类似的靶向功能。这项资助的基本假设是，通过泛素样蛋白的去缀合来调节Ubl途径可能同样重要，在癌症中起作用，调节生长和凋亡。逆转UbI蛋白缀合的酶（类泛素蛋白酶，ULP）是进一步研究的有吸引力的靶点，因为这些修饰的逆转预期会干扰功能。由于它们是蛋白酶，大量的工作提出了有效的药理学干预方法。此外，通过过度表达解结合酶来干扰这些途径比阻止UbI结构域的附着更容易（概念上和实际上）;这种方法需要基因敲除或显性阴性方法。了解这些解结合酶的作用需要我们更多地了解这类酶，它们的底物和它们的调节。将合成一系列ULP的抑制剂和底物，并用于测试三个特定的假设。首先，威尔金森博士将测试哺乳动物COP 9信号体的一个完整亚基能够逆转cullin的Nedd 8修饰的假设。他还将通过鉴定和干扰逆转这种修饰的酶的功能来检验ISG 15对蛋白质的修饰是干扰素应答的组成部分的假设。他将确定促凋亡Ubl FAT 10的缀合是否可逆。最后，他将测试HAUSP和/或SENPI是从早幼粒细胞白血病蛋白中去除SUMO-1的Ubl的假设，触发PML的分解。