Role of MRK in DNA Damage Response

MRK 在 DNA 损伤反应中的作用

• 批准号: 6871592
• 负责人: ROSAMARIA RUGGIERI
• 金额: $ 26.95万
• 依托单位: FEINSTEIN INSTITUTE FOR MEDICAL RESEARCH
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-28 至 2008-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6871592
• 关键词: DNA damage; DNA repair; RNA interference; SDS polyacrylamide gel electrophoresis; biological signal transduction; cell cycle; cell growth regulation; cell proliferation; immunoprecipitation; ionizing radiation; mass spectrometry; molecular oncology; neoplasm /cancer radiation therapy; neoplastic cell; neoplastic process; phosphorylation; protein kinase; protein structure function; radiation resistance; radiation sensitivity; radiobiology; site directed mutagenesis; western blottings

DESCRIPTION (provided by applicant): The cellular response to DNA damage contributes to radiation resistance in cancer by inducing cell cycle arrest and allowing time for damage repair. The long-term objective of this proposal is to identify signaling components of the DNA damage response that could be targeted to decrease radiation resistance in cancer cells. The surveillance mechanisms that control cell cycle arrest are called checkpoints and consist of a complex network of signaling pathways that control DNA repair as well as cell cycle arrest among other functions. The ATM-Chk2/Chkl-Cdc25A cascade, downstream of the BRCT-motif-containing proteins MCD1, Nbsl and 53BP1, plays an important role in gamma-radiation-induced cell cycle arrest in S and G2 phase. The protein kinase MRK is activated by gamma-radiation and contributes to S-phase and G2-phase cell cycle arrest. MRK was found to participate in the gamma-radiation-induced Chk2 activation by directly phosphorylating Chk2. In addition, MRK knockdown by RNA interference reduces 53BP1 localization to sites of DNA damage and sensitizes cancer cells to the lethal effects of gamma-radiation. The goal of this study is to elucidate the mechanism through which MRK contributes to DNA-damage-induced cell cycle arrest by testing the following hypothesis: MRK operates downstream ofMDC1, Nbsl, 53BP1 and ATM, in the cascade that leads to Chk2 activation and Cdc25A degradation in response to, gamma-radiation. The specific aims will test these hypotheses by: 1) Defining the elements that operate in the MRK pathway in response to gamma-radiation; and 2) Defining the molecular mechanism of MRK activation through structure-function studies. The molecular analysis of the function of MRK will improve our understanding of cell cycle checkpoint regulation following DNA damage and could identify novel targets for the development of antineoplastic agents aimed at decreasing tumor radiation resistance.

描述（由申请人提供）：细胞对 DNA 损伤的反应通过诱导细胞周期停滞并为损伤修复留出时间，从而有助于癌症的抗辐射性。该提案的长期目标是确定 DNA 损伤反应的信号成分，这些信号成分可用于降低癌细胞的辐射抵抗力。控制细胞周期停滞的监视机制称为检查点，由复杂的信号通路网络组成，控制 DNA 修复以及细胞周期停滞等功能。 ATM-Chk2/Chk1-Cdc25A级联，位于含有BRCT基序的蛋白质MCD1、Nbsl和53BP1的下游，在γ辐射诱导的S和G2期细胞周期停滞中发挥重要作用。蛋白激酶 MRK 由伽马辐射激活，有助于 S 期和 G2 期细胞周期停滞。研究发现 MRK 通过直接磷酸化 Chk2 来参与伽马辐射诱导的 Chk2 激活。此外，RNA 干扰导致的 MRK 敲除减少了 53BP1 在 DNA 损伤位点的定位，并使癌细胞对伽马辐射的致命效应敏感。本研究的目的是通过测试以下假设来阐明 MRK 促进 DNA 损伤诱导的细胞周期停滞的机制：MRK 在 MDC1、Nbsl、53BP1 和 ATM 下游发挥作用，在伽马辐射响应下导致 Chk2 激活和 Cdc25A 降解的级联中。具体目标将通过以下方式检验这些假设： 1) 定义响应伽马辐射而在 MRK 通路中起作用的元素； 2）通过结构功能研究定义MRK激活的分子机制。对 MRK 功能的分子分析将提高我们对 DNA 损伤后细胞周期检查点调节的理解，并可以确定开发旨在降低肿瘤辐射耐受性的抗肿瘤药物的新靶点。