权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Mechanisms of ATM activation

ATM 激活机制

基本信息

批准号：
8444602
负责人：
TANYA T PAULL
金额：
$ 22.84万
依托单位：
UNIVERSITY OF TEXAS AT AUSTIN
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-05-01 至 2015-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8444602
关键词：
ATM Signaling Pathway ATM activation ATM deficient ATM function Acetylation Address Apoptosis Ataxia Telangiectasia Ataxia-Telangiectasia-Mutated protein kinase Binding Biochemical Cell Cycle Arrest Cell Cycle Checkpoint Cells Chronic Complex DNA DNA Damage DNA Double Strand Break DNA Repair DNA biosynthesis Databases Dimerization Eukaryotic Cell Exhibits Exposure to Frequencies Genomic Instability Genotype Goals Health Homodimerization Human Hydrogen Peroxide Hypersensitivity In Vitro Investigation Ionizing radiation Malignant Neoplasms Mammalian Cell Mediating Metabolic Molecular Mus Mutate Nerve Degeneration Oncogenic Oxidative Stress Pathway interactions Patients Phosphorylation Population Process Proteins Recombinants Recruitment Activity Regulation Repair Complex Resistance Role Signal Transduction Site System Testing Tumor Suppressor Proteins Work ataxia telangiectasia mutated protein base biological adaptation to stress dimer inhibitor/antagonist monomer mutant novel oxidation oxidative damage prevent progressive neurodegeneration protein protein interaction reconstitution response sensor tumor tumor progression tumorigenesis

项目摘要

DESCRIPTION (provided by applicant): The ATM protein kinase is a master regulator of the cellular response to chromosomal DNA double-strand breaks. This type of DNA damage occurs during DNA replication, as a result of damage from metabolic intermediates, and after exposure to ionizing radiation and radiomimetic compounds. In response to DNA damage, ATM phosphorylates many cellular substrates, several of which are known tumor suppressors in humans. Phosphorylation of these substrates initiates cell cycle arrest, apoptosis, and DNA repair. Loss of ATM, as seen in patients with Ataxia-Telangiectasia (A-T), results in increased genomic instability, a complete loss of double-strand break-induced cell cycle checkpoints, and a significant increase in cancer frequency. A-T patients also suffer from severely reduced responses to oxidative stress as well as to DNA double-strand breaks, and chronic oxidative stress has been shown to contribute to neurodegeneration seen in these patients. The ATM protein in mammalian cells exists as an inactive homodimer and becomes activated by DNA double-strand breaks through association with the DNA repair complex Mre11/Rad50/Nbs1 (MRN). In previous work we have reconstituted the ATM activation process with recombinant purified proteins and showed that MRN acts as a double-strand break sensor for ATM. In the current proposal we use this system to characterize the mechanisms of ATM activation in greater detail and investigate novel pathways of ATM regulation. Specific Aim 1 addresses the molecular basis of ATM activation through oxidative damage and seeks to identify ATM domains and residues involved in this process. Analysis of specific mutants deficient in oxidative activation will be used to investigate the functions of this pathway in human cells. Aim 2 investigates the mechanistic role of Nbs1 in ATM activation by double-strand breaks and addresses the functional relationship between MRN and ATM in greater detail through the identification of MRN-ATM protein-protein interactions and ATM homodimerization motifs. Aim 3 characterizes the roles of other proteins that are known to regulate ATM activation and substrate phosphorylation in human cells, and investigates the functional effects of ATM acetylation and autophosphorylation. The overall goal of the project is to biochemically decipher the many layers of regulation that govern ATM activity in human cells in order to understand how this important protein responds so rapidly and specifically to DNA double-strand breaks and oxidative stress.

描述（由申请方提供）：ATM蛋白激酶是细胞对染色体DNA双链断裂反应的主要调节因子。这种类型的DNA损伤发生在DNA复制过程中，由于代谢中间体的损伤，以及暴露于电离辐射和拟辐射化合物后。作为对DNA损伤的反应，ATM使许多细胞底物磷酸化，其中一些是已知的人类肿瘤抑制剂。这些底物的磷酸化启动细胞周期停滞、凋亡和DNA修复。在共济失调-毛细血管扩张症（A-T）患者中观察到的ATM缺失导致基因组不稳定性增加，双链断裂诱导的细胞周期检查点完全缺失，以及癌症频率显著增加。A-T患者对氧化应激以及DNA双链断裂的反应也严重降低，并且慢性氧化应激已被证明有助于在这些患者中观察到的神经变性。ATM蛋白在哺乳动物细胞中以无活性的同源二聚体形式存在，并通过与DNA修复复合物Mre 11/Rad 50/Nbs 1（MRN）结合而被DNA双链断裂激活。在以前的工作中，我们已经重建了ATM激活过程中重组纯化的蛋白质，并表明，MRN作为ATM的双链断裂传感器。在目前的建议中，我们使用这个系统来更详细地描述ATM激活的机制，并研究ATM调节的新途径。具体目标1通过氧化损伤解决ATM激活的分子基础，并试图确定ATM结构域和残基参与这一过程。对氧化活化缺陷的特定突变体的分析将用于研究该途径在人类细胞中的功能。目的2研究Nbs 1在ATM激活中的作用机制，通过鉴定MRN-ATM蛋白质-蛋白质相互作用和ATM同源二聚体基序，更详细地阐明MRN和ATM之间的功能关系。目的3表征已知调节ATM活化和底物磷酸化的其他蛋白质在人类细胞中的作用，并研究ATM乙酰化和自磷酸化的功能效应。该项目的总体目标是从生物化学的角度解读人类细胞中ATM活性的多层调控机制，以了解这种重要的蛋白质如何快速特异地响应DNA双链断裂和氧化应激。