Regulation of the ATR Checkpoint Kinase by DNA Damage

描述（由申请人提供）：在细胞分裂和发育过程中如何维持基因组稳定性是细胞和发育生物学的一个基本问题，对包括癌症在内的人类疾病有很强的影响。为了维持基因组的稳定，细胞依赖于几个细胞过程的协同作用，包括忠实的DNA复制、有效的DNA修复和协调的细胞周期进程。DNA损伤信号通路，也被称为DNA损伤检查点，是这些过程的中心导体。共济失调毛细血管扩张突变和rad3相关（ATR）检查点激酶是检查点通路的主要调节因子。作为广泛的DNA损伤和基因组不稳定的主要细胞传感器，ATR在保护基因组，特别是在DNA复制过程中起着关键作用。受损的ATR信号增加了基因组的不稳定性，促进了癌症的发生和进展。此外，ATR被辐射和许多化疗药物激活，ATR反应缺陷使癌细胞对外在和内在DNA损伤高度敏感。鉴于ATR在DNA损伤反应和癌症治疗中的关键作用，了解ATR激活及其功能的分子机制具有重要意义。更好地了解ATR的调控和功能对于开发针对癌细胞基因组不稳定性的新癌症疗法至关重要。我们的主要目标是了解ATR如何在DNA损伤反应中转化为完全活跃的激酶。此外，我们将研究ATR- Chk1信号通路如何在DNA损伤反应的早期阶段被激活，以及它如何在反应的后期被失活。我们的研究将结合生化、细胞生物学和蛋白质组学方法。特别是，我们将分析DNA损伤后ATR及其调控物和效应器如何被修饰，以及这些修饰如何调节其功能。我们还将系统地开发一个体外生化分析系统，以概括DNA损伤对ATR的激活。这些研究将使我们能够清楚地定义导致ATR激活的关键分子事件，以及通过ATR- chk1途径协调信号传导的关键事件。这些研究可能会显著推进ATR激活的现有模型，为未来研究揭示ATR的全部生物学功能及其在靶向癌症治疗中的意义提供分子基础。

DESCRIPTION (provided by applicant): How genomic stability is maintained during cell divisions and development is a fundamental question for Cell and Developmental Biology with a strong implication in human diseases including cancer. To maintain a stable genome, cells rely on the concerted action of several cellular processes, including faithful DNA replication, efficient DNA repair, and coordinated cell cycle progression. The DNA damage-signaling pathway, also known as the DNA damage checkpoint, is the central conductor of these processes. The ataxia-telangiectasia mutated and rad3-related (ATR) checkpoint kinase is a master regulator of the checkpoint pathway. As the main cellular sensor of a broad spectrum of DNA damage and genomic instability, ATR plays a key role in protecting the genome, particularly during DNA replication. Compromised ATR signaling increases genomic instability, contributing to the development and progression of cancer. Furthermore, ATR is activated by radiation and many chemotherapeutic drugs, and defective ATR response renders cancer cells highly sensitive to extrinsic and intrinsic DNA damage. Given the pivotal role of ATR in DNA damage response and cancer therapy, it is of great importance to understand the molecular mechanisms by which ATR is activated and by which it functions. A better understanding of the regulation and function of ATR will be critical for the development of new cancer therapies to target the genomic instability in cancer cells. Our main goal in this proposal is to understand how ATR is transformed into a fully active kinase during DNA damage response. Furthermore, we will investigate how the ATR- Chk1 signaling pathway is activated during the early stage of DNA damage response, and how it is deactivated at the late stage of the response. Our studies will combine biochemical, cell biological, and proteomic approaches. In particular, we will analyze how ATR and its regulators and effectors are modified after DNA damage, and how these modifications regulate their functions. We will also systematically develop an in vitro biochemical assay system to recapitulate the activation of ATR by DNA damage. These studies will allow us to clearly define the key molecular events that lead to ATR activation, as well as the key events that orchestrate the signaling through the ATR-Chk1 pathway. These studies may significantly advance the current model of ATR activation, providing the molecular basis for future studies to reveal the full biological functions of ATR and its implications in targeted cancer therapy. PUBLIC HEALTH RELEVANCE: Compromised ATR function leads to increased genomic instability, which has been linked to cancer, developmental defects, and premature aging. Understanding the molecular mechanisms by which ATR is activated and by which it functions will help elucidate the underlying mechanisms of these diseases, and help develop new therapeutic strategies for the treatment of these diseases.