The Mammalian Cell Cycle Control and Tumor Genesis

描述（由申请人提供）：这是CA65572的第二次竞争性更新，该研究旨在了解哺乳动物细胞周期控制和肿瘤发生的长期目标。回顾过去10年的历程，我们高兴地看到我们为这一领域做出的贡献，更值得注意的是，在这一领域工作的其他人共同取得了进步。我们自己的研究重点已经从1993年新发现的第一个CDK抑制剂p21的功能和调控发展到第二个资助期的Arf-Mdm2-p53通路的发现和研究。本申请提出的研究将集中于确定p53的细胞质控制，这一领域正在成为p53调控和肿瘤抑制的关键调控步骤。导致这一建议的是我们和其他人最近的三个发现：(i)在调节p53的多个应激检查点途径中广泛利用核出口；（ii） ROC1和ROC2作为cullin家族E3泛素连接酶的催化亚基的发现，以及（iii）两个roc依赖的连接酶PARC和CUL7与p53结合并定位于细胞质中。

DESCRIPTION (provided by applicant): This is the second competing renewal of CA65572, an investigation that is aimed at the long-term goal of understanding mammalian cell cycle control and tumorigenesis. Looking back at the journey of the last 10 years, we are pleased to see the contribution we made to the field and, more remarkably, the advancement achieved collectively by others working in this field. The focus of our own research has moved forward from determining the function and regulation of the newly discovered first CDK inhibitor, p21 in 1993, to the discovery and study of the Arf-Mdm2-p53 pathway during the second funding period. The research proposed in this application will focus on determining the cytoplasmic control of p53, an area that is emerging as a critical regulatory step in p53 regulation and tumor suppression. Leading to this proposal are three findings we and others made recently: (i) broad utilization of nuclear export by multiple stress checkpoint pathways in regulating p53; (ii) the discovery of ROC1 and ROC2 as the catalytic subunit of cullin family E3 ubiquitin ligases, and (iii) two ROC-dependent ligases, PARC and CUL7, bind to p53 and localize in the cytoplasm. Four specific aims are proposed to determine: (Aim I) The functional consequence of PARC-p53 interaction, (Aim II) The mechanisms of PARC and CUL7 function, (Aim HI) The function of DOC domain in PARC and CUL7, and (Aim IV) The function of RBR domain of PARC. This proposal combines our strength and success in four areas: genetic and tumor analysis in mouse with targeted mutations; biochemical characterization of ubiquitin ligases; cellular studies of p53 export and p53 checkpoint pathways, and IP-Mass Spec-based protein complex characterization. We anticipate that these comprehensive and multi-disciplinary studies will lead to a better understanding of cytoplasmic control of p53, the function and mechanism of the ubiquitin pathway and the process of tumor suppression.