Functions of Ub-like Proteins & Processing Proteases

Ub 样蛋白的功能

• 批准号: 6785957
• 负责人: KEITH D WILKINSON
• 金额: $ 30.4万
• 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/6785957
• 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(申请人提供)：去泛素酶(DUBS，也称为去结合酶)是一种重要的调节酶，它处理泛素基因家族的初级基因产物，逆转泛素与细胞蛋白质的结合，并分解多聚泛素链，这些多泛素链针对蛋白质被蛋白酶体降解。因此，它们调节蛋白分解，从而在细胞周期、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中进行进展。直到最近，人们才意识到，用其他泛素样蛋白(UbL)修饰蛋白质具有类似的靶向功能。这项拨款的基本假设是，通过去结合泛素样蛋白来调节Ub1通路可能与在癌症、生长和凋亡的调节中发挥作用一样重要。逆转UBI蛋白结合的酶(泛素样蛋白蛋白酶，ULP)是有吸引力的进一步研究的目标，因为这些修饰的逆转预计会干扰功能。由于它们是蛋白水解酶，大量的研究工作提出了有效的药物干预方法。此外，与阻止UBI结构域的连接相比，通过过度表达去结合酶来干扰这些途径更容易(在概念上和实践上)；这种方法需要基因敲除或显性阴性方法。要了解这些去共轭酶的作用，我们需要更多地了解这类酶，它们的底物及其调节。将合成一系列ULPS的抑制剂和底物，并用来检验三个特定的假设。首先，威尔金森博士将检验这一假设，即哺乳动物COP9信号体的一个完整亚基能够逆转库林斯的Nedd8修饰。他还将通过识别并干扰逆转这种修饰的酶的功能，来检验ISG15对蛋白质的修饰是干扰素反应的组成部分的假设。他将确定促凋亡的Ubl FAT10的结合是否可逆。最后，他将检验Hausp和/或SENPI是从早幼粒细胞白血病蛋白中移除SUMO-1的UbL，从而触发PML的分解的假设。