MOLECULAR MECHANISMS OF MAMMALIAN CHECKPOINT PATHWAYS

哺乳动物检查点通路的分子机制

• 批准号: 6158876
• 负责人: Christine Elizabeth Canman
• 金额: $ 23.36万
• 依托单位: ST. JUDE CHILDREN'S RESEARCH HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-05-15 至 2005-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6158876
• 关键词: DNA damage; biological signal transduction; cell cycle proteins; cell growth regulation; ionizing radiation; phosphoprotein phosphatase; phosphoproteins; phosphorylation; posttranslational modifications; protein kinase; protein protein interaction; threonine; tissue /cell culture

DESCRIPTION: (From Abstract) Cell cycle checkpoints are surveillance mechanisms that induce growth arrest responses to ensure genetic fidelity and stability. Absence of checkpoint function can be associated with increased sensitivity to ionizing radiation (IR) and with genetic diseases such as the cancer prone disease ataxia telangiectasia that is caused by mutations within the ATM gene. The genes required for yeast checkpoint functions are well known but have not been fully characterized at the biochemical level. Human homologs for these genes have now been identified and include the main effector proteins kinases ATM and ATR; a complex of proteins believed to act upstream of ATM and ATR (HuRad1, HuHus1, HuRad9, and HuRad1; and downstream effector kinases HuChk1 and HuCds1 (Chk2) that appear to mediate growth arrest in G2 by targeting cdc25C. It has been shown that HuCds1 is activated in an ATM-dependent manner in response to IR. Experiments will be performed to determine whether ATM targets HuCds1 in response to IR and whether HuCds1 is a major effector of ATM-controlled pathways. Other mechanisms for the regulation of HuCds1 in response to DNA damage will be explored by determining whether other proteins bind to the fork head associated (FHA) domain of HuCds1 and modulate its activity in response to DNA damage. To begin to understand the functions of HuRad1, HuHus1, HuRad9, and HuRad17, dominant negative inhibitors will be designed to disrupt HuRad17 function and the HuRad1, HuHus1, and HuRad9 complex. These inhibitors will be tested as to whether their expression in cells interferes with the regulation of ATM kinase in response to IR and produce AT-like checkpoint phenotypes. Defining the molecular functions of these genes will not only improve our understanding of cell cycle regulation following DNA damage, but may also identify new gene products that could be targeted for the development of radiosensitizers.

描述：（来自摘要）细胞周期检查点是监视机制 其诱导生长停滞反应以确保遗传保真度和稳定性。 检查点功能的缺乏可能与对以下因素的敏感性增加有关： 电离辐射（IR）和遗传性疾病，如癌症倾向 疾病共济失调毛细血管扩张症是由ATM基因内的突变引起的。 酵母检查点功能所需的基因是众所周知的，但还没有 在生化水平上得到了充分的表征。这些基因的人类同系物 目前已鉴定出一些基因，包括主要的效应蛋白激酶 ATM和ATR;一种被认为在ATM和ATR上游起作用的蛋白质复合物 （HuRad 1、HuHus 1、HuRad 9和HuRad 1;以及下游效应激酶HuChk 1和HuChk 2） HuCds 1（Chk 2）似乎通过靶向cdc 25 C介导G2中的生长停滞。 已经表明HuCds 1在细胞内以ATM依赖性方式被激活， 将进行实验以确定ATM是否靶向 HuCds 1对IR的反应以及HuCds 1是否是IR的主要效应子。 ATM控制路径其他调节HuCds 1的机制 对DNA损伤的反应将通过确定其他蛋白质是否 结合HuCds 1的叉头相关（FHA）结构域并调节其 对DNA损伤的反应。开始理解的功能 HuRad 1、HuHus 1、HuRad 9和HuRad 17，显性负性抑制剂，将被 旨在破坏HuRad 17功能以及HuRad 1、HuHus 1和HuRad 9 复杂.这些抑制剂将被测试，以确定它们是否在细胞中表达。 细胞干扰ATM激酶对IR的调节， 产生AT样检查点表型。定义的分子功能 这些基因不仅能提高我们对细胞周期调控的理解， 但也可能发现新的基因产物， 用于开发放射增敏剂。