Functional Analysis of Rad23 Protein

描述（由申请人提供）：尽管在理解核苷酸切除修复（NER）的生化基础方面取得了重大进展，但仍无法治愈着色性干皮病、科凯恩综合征、范可尼贫血和其他DNA修复缺陷。目前的治疗重点是缓解症状和改善生活质量。 泛素/蛋白酶体系统（UPS）是细胞内蛋白质降解的重要机制，参与细胞周期调控、应激反应、信号转导和DNA修复等。我们确定NER蛋白Rad 4是高度不稳定的，并且被蛋白酶体快速降解。值得注意的是，许多额外的DNA修复蛋白具有蛋白质降解功能，包括Rad 6，Rad 7，Rad 16和FANCL。 在过去的15年里，我的实验室一直在研究蛋白质降解在DNA修复中的作用。我们确定Rad 4在与DNA修复因子Rad 23形成复合物时是稳定的。Rad 23还可以结合蛋白酶体并递送泛素化底物。我们最近发现，蛋白酶体在核周围的定位是DNA修复所必需的。本研究将采用遗传学、生物化学和细胞生物学方法研究UPS在核苷酸切除修复中的作用。我们将描述蛋白质的交通蛋白酶体，并确定如何核底物，包括Rad 4，针对蛋白酶体。这些机制研究预计将产生广泛的影响，因为它们将表明蛋白酶体运输代表了细胞内蛋白质降解中以前未知的调节过程。 公共卫生相关性：拟议研究的主要目的是研究蛋白质降解在DNA修复中的作用。着色性干皮病和Cockayne综合征是研究充分的DNA修复缺陷，没有治疗或治愈。我们的研究可以为鉴定候选蛋白质和可被治疗剂靶向的生化功能铺平道路。

DESCRIPTION (provided by applicant): Despite significant advances in understanding the biochemical basis of nucleotide excision repair (NER), there is no cure for individuals with Xeroderma pigmentosum, Cockayne Syndrome, Fanconi Anemia, and other DNA repair defects. Current therapy is focused on relieving symptoms and improving quality of life. The ubiquitin/proteasome system (UPS) of interacellular protein degradation has been extensively studied, and is implicated in cell cycle control, stress response, signal transduction, and DNA repair. We determined that the NER protein Rad4 is highly unstable, and is rapidly degraded by the proteasome. Remarkably, a number of additional DNA repair proteins have protein degradation functions, including Rad6, Rad7, Rad16 and FANCL. My laboratory has, for the past 15 years, investigated the role of protein degradation in DNA repair. We determined that Rad4 is stabilized when it forms a complex with the DNA repair factor, Rad23. Rad23 can also bind the proteasome and deliver ubiquitinated substrates. We recently discovered that the localization of proteasomes at the nuclear periphery is required for DNA repair. The studies proposed here will use genetic, biochemical and cell biological approaches to investigate the role of the UPS in nucleotide excision repair. We will characterize the proteins that traffic proteasomes, and determine how nuclear substrates, including Rad4, are targeted to the proteasome. These mechanistic studies are expected to have a broad impact, as they will show that proteasome trafficking represents a previously unknown regulatory process in intracellular protein degradation. PUBLIC HEALTH RELEVANCE: The primary objective of the proposed studies is to investigate the role of protein degradation in DNA repair. Xeroderma pigmentosum and Cockayne Syndrome are well studied DNA repair defects for which there is no treatment or cure. Our studies could pave the way towards identification of candidate proteins and biochemical functions that can be targeted by therapeutic agents.