Regulation of the G1 Phase by the Ubiquitin Pathway

描述(申请人提供)：SCF泛素连接酶复合体，组成 在三个主要的亚基中，Skp1、cull和一个F-box蛋白(FBP)调节 蛋白质降解对多种细胞增殖调节物质的底物专一性 由作为底物的不同FBP亚基决定 识别因素。首席调查员证明， F-box蛋白Skp2是机器的限速组件，它 泛素化细胞周期抑制因子p27，而Skp2需要其 与Cks1的物理结合以高亲和力结合p27。校长 研究人员对泛素途径的兴趣导致了对 一个由26个人类F-box蛋白组成的家族，并发现其中一名成员 这个被称为β-trcp的家族调节原癌基因的稳定性。 β-连环蛋白。 在目标1中，SCFskp2和Cks1的调控和作用 将研究哺乳动物的细胞分裂周期。特别是，它的功能 Ser-76上Skp2的磷酸化和选择性剪接Skp2的作用， 最近由首席调查员确定的，将进行研究。在目标2中，一个 使用同源基因使β-Trcp基因失活的突变小鼠 将对复合进行研究。使用这种方法，首席调查员 将决定β-Trcp在生长发育中的作用以及 它在特定组织和器官中的作用。首席调查员将研究 SCF-β-Trcp如何调控细胞增殖和 免疫反应。首席调查员将能够确定 缺乏β-Trcp对其可能底物的体内效应。最后，在AIM中 3首席调查员将调查另一名成员的职能 新发现的人类FBP家族，即Fbl3，他发现这是 定位在中心体上。根据目标3，首席调查员还将 克隆并鉴定他发现的三种特定相关的蛋白质 Fb13基因在体内的表达。

DESCRIPTION (provided by applicant): SCF ubiquitin ligases complexes, composed of three major subunits, Skp1, Cull, and an F-box protein (Fbp), regulate the proteolysis of many regulators of cell proliferation The substrate specificity of SCFs is determined by distinct Fbp subunits that act as substrate recognition factors. It was demonstrated by the principal investigator that the F-box protein Skp2 is a rate-limiting component of the machinery that ubiquitinylates the cell cycle inhibitor p27, and that Skp2 requires its physical association to Cksl to bind p27 at high affinity. The principal investigator's interest in the ubiquitin pathway lead to the identification of a family of 26 human F-box proteins and to the discovery that one member of this family, called beta-Trcp, regulates the stability of the proto-oncogene beta-catenin. In Aim 1 the regulation and the role of SCFskp2 and Cks1 in the control of the mammalian cell division cycle will be studied. In particular, the function of Skp2 phosphorylation on Ser-76 and the role of an alternatively spliced Skp2, recently identified by the principal investigator, will be studied. In Aim 2, a mutant mouse in which the beta-Trcp locus has been inactivated using homologous recombination will be studied. Using this approach the principal investigator will determine the function of beta-Trcp in growth and development as well as its role in specific tissues and organs. The principal investigator will study how SCF-beta-Trcp regulates processes such as cellular proliferation and the immune response. The principal investigator will be able to determine the in vivo effects of lack of beta-Trcp on its putative substrates. Finally, in Aim 3 the principal investigator will investigate the function of another member of the newly identified human Fbp family, namely Fbl3, which he has found to be localized on the centrosome. Under Aim 3, the principal investigator will also clone and characterize three proteins that he has found associated specifically with Fb13 in vivo.