REGULATION OF THE CELL CYCLE INHIBITOR P27KIPL BY REDOX

通过氧化还原调节细胞周期抑制剂 P27KIPL

• 批准号: 6167158
• 负责人: ROBERT J SHEAFF
• 金额: $ 11.14万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-03-01 至 2003-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6167158
• 关键词: breast neoplasms; cell cycle proteins; cyclin dependent kinase; cyclins; cysteine; enzyme activity; enzyme inhibitors; microtubule associated protein; oxidation reduction reaction; phosphoproteins; site directed mutagenesis; tissue /cell culture; transfection; tumor suppressor proteins

DESCRIPTION: (Applicant's Description) Cell proliferation is tightly controlled to prevent loss of growth control, a hallmark of cancer. The cell cyclel inhibitor p27kipl, although seldom deleted or mutated, nevertheless plays an important role as tumor suppressor in preventing breast cancer. Decreased p27 protein levels correlate with a more aggressive disease, higher rates of reoccurrence, and poorer long term survival for young breast cancer patients. The clinical observations highlight an important problem that must be addressed by biologists--what are the mechanisms controlling p27 protein levels, and how are they compromised in tumorigenesis? p27 is thought to be regulated mainly by translational or proteolytic mechanisms. We have recently identified the reduction/oxidation (redox) environment as a new way of regulating p27 structure and function. Preliminary results indicate the cell cycle inhibitor p27 can exist in an oxidized or a reduced state. Only reduced p27 functions as an inhibitor of cyclin dependent kinases--the oxidized form of p27 functions solely as a CDK substrate. We and others have proposed that p27 degradation is controlled by phosphorylation, and that the kinase responsible for determining p27 protein levels may be cyclin E-CDK2. Thus, the preliminary data provide a convincing rationale for redox regulation of p27: oxidation not only prevents CDK inhibition, but it may favor p27 phosphorylation and elimination from the cell. The focus of this proposal is to characterize p27 redox regulation in a system of purified proteins. Amino acids(s) involved in redox regulation will be identified by mutagenesis. Chemical agents capable of modulating redox environment will be examined for their ability to switch p27 between inhibitor and substrate roles. A transient transfection procedure will then be used to express wild type and mutant p27 cDNAs in tissue culture cells. p27 redox state and activity against cyclin-CDKs will be examined to identify any differences which may be due to redox regulation. Chemical agents will be examined for their ability to alter redox environment in cells and hence p27 structure and function. The long term objective is to determine whether p27 is redox regulated in normal or aberrant cell physiology, and to ascertain whether targeting p27 redox regulation represents a novel way to intervene in the development of breast cancer.

描述：（申请人的描述） 细胞增殖受到严格控制，以防止失去生长控制， 癌症的标志细胞周期抑制因子p27 kipl虽然很少缺失， 或突变，但在肿瘤抑制中起着重要作用， 预防乳腺癌。p27蛋白水平降低与更多的 侵袭性疾病，复发率较高，长期预后较差 年轻乳腺癌患者的生存率。临床观察结果强调 生物学家必须解决的一个重要问题-- 控制p27蛋白水平的机制，以及它们如何在 肿瘤发生p27被认为主要通过翻译或 蛋白水解机制我们最近发现了还原/氧化 （氧化还原）环境作为调节p27结构和功能的新方式。 初步结果表明，细胞周期抑制剂p27可以存在于细胞中。 氧化态或还原态。只有减少的p27作为一种抑制剂的功能， 细胞周期蛋白依赖性激酶--p27的氧化形式仅作为CDK起作用 衬底我们和其他人已经提出，p27降解是由以下因素控制的： 磷酸化，并且负责决定p27蛋白的激酶 水平可以是细胞周期蛋白E-CDK 2。因此，初步数据提供了一个令人信服的 p27氧化还原调节的基本原理：氧化不仅阻止CDK 抑制，但它可能有利于p27磷酸化和消除从 cell.该提案的重点是表征p27氧化还原调节在一个细胞中的作用。 纯化蛋白质的系统。参与氧化还原调节的氨基酸将 通过诱变鉴定。能够调节氧化还原的化学试剂 将检查环境在抑制剂之间切换p27的能力 和底物的作用。然后将使用瞬时转染程序， 在组织培养细胞中表达野生型和突变型p27 cDNA。p27氧化还原 将检查针对细胞周期蛋白-CDK状态和活性以鉴定任何 这可能是由于氧化还原调节的差异。化学制剂将 检查它们改变细胞中氧化还原环境的能力，从而改变p27 结构和功能。长期目标是确定p27是否是 氧化还原调节正常或异常细胞生理学，并确定 靶向p27氧化还原调节是否代表了一种新的干预方法， 乳腺癌的发展。