CyclinE/Cdk2相关蛋白Ankrd17在细胞周期调控中的功能研究

项目名称： CyclinE/Cdk2相关蛋白Ankrd17在细胞周期调控中的功能研究

项目编号： No.30871238

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 叶昕

作者单位： 中国科学院微生物研究所

项目金额： 34万元

中文摘要： CyclinE/Cdk2在细胞周期的G1/S检验点转换过程中发挥着极其关键的作用。目前已经发现了一些与CyclinE/Cdk2相互作用的蛋白参与细胞周期的调控，但是CyclinE/Cdk2调控细胞周期的详尽的信号转导网络尚未明晰。我们通过TAP亲和纯化技术筛选到CyclinE/Cdk2新相互作用蛋白－锚蛋白Ankrd17。目前国际上对Ankrd17全蛋白的功能尚无文献报道，我们对Ankrd17调控细胞周期的机理进行系统的研究。本研究通过体外激酶反应及质谱分析等手段，证实Ankrd17为Cyclin E/Cdk2的底物，并定位其磷酸化位点; 通过免疫荧光染色、RNAi干扰及流式细胞术等方法发现Ankrd17能促进细胞周期的进行, 同时我们发现Ankrd17通过调控DNA复制相关蛋白Cdc6和PCNA与DNA的结合而参与DNA复制; 研究结果表明Ankrd17是细胞周期G1/S期转换过程中的一种正调控蛋白。 我们的研究结果有助于进一步理解CyclinE/Cdk2激酶复合体在细胞周期调控及肿瘤发生过程中的作用，进而为寻找新的抗肿瘤治疗靶标提供理论依据。

中文关键词： cyclinE/Cdk2蛋白激酶；锚蛋白ankrd17; 细胞周期；DNA复制；G1/S期转换

英文摘要： In higher eukaryotes, controlled cell proliferation is required for normal growth and development. Deregulation of cell division pathways can lead to tumour formation and carcinogenesis. Understanding the mechanism of cell cycle is pivotal to understanding the development of human cancer. One fundamental biochemical process which controls cell cycle is protein phosphorylation mediated by the cyclin and cyclin-dependent kinases (CDKs). Our current research has identified a novel cyclin E/Cdk2 substrate called Ankrd17 (ankyrin repeat protein 17) by the TAP tag purification. We found that overexpression of Ankrd17 promotes S phase entry, whereas depletion of Ankrd17 expression by small interfering RNA inhibits DNA replication and blocks cell cycle progression as well as up-regulates the expression of p53 and p21. Ankrd17 is localized to the nucleus and interacts with DNA replication factors including MCM family members, Cdc6 and PCNA. Depletion of Ankrd17 results in decreased loading of Cdc6 and PCNA onto DNA suggesting that Ankrd17 may be directly involved in the DNA replication process. Our study indicates that Ankrd17 is an important downstream effector of cyclin E/Cdk2 and positively regulates G1/S transition. Current research involves characterizing the newly identified cyclinE/Cdk2 associated protein Ankrd17 and its function in cell cycle regulation. These studies will lead to an increased understanding of the molecular mechanisms of cell cycle providing insight into the development of human cancer.

英文关键词： cyclin E/Cdk2; ankryrin repeat protein 17; cell cycle; DNA relication; G1/S transition