NOVEL CDK6 ASSOCIATED PROTEIN

细胞周期进程是一个受到严格调控的事件，即放松调控 这是癌症的一个标志。真核细胞周期是 受细胞周期蛋白依赖性激酶的时间关联控制 (CDK)与Cyclin合作伙伴，导致这些 以及关键底物的随后的磷酸化。 哺乳动物的D型细胞周期蛋白及其CDK4和CDK6是 G1期进程的重要调节者；人们对此知之甚少 然而，这些CDK/Cyclin复合体是受调控的。这项建议 描述了一种新基因的分子克隆和生化特性。 CDK6免疫沉淀物中发现的新的约28 kDa蛋白(P28) 含有从原代人类T细胞中分离的D型细胞周期蛋白 G1期。奇怪的是，p28与产生的抗体发生免疫反应。 P27KIP1，一种新近发现的cdk抑制剂，但与 P27KIP1。这些发现提出了一种有趣的可能性，即p28 代表了一种新的CDK抑制剂，它与CDK6/ 细胞周期蛋白D复合体对G_1期有重要的调节作用 控制力。了解p28的cdna序列将使其表达和 与各种cdk/细胞周期蛋白复合体的结合 待分析的细胞周期。P28影响蛋白激酶的可能性 CDK6/Cyclin D复合体或其他CDK/Cyclin复合体的活性 将会被调查。P28所需的p28上的最小域 与CDK/Cyclin络合物的结合和活性将是 已映射。最后，瞬时转染过表达p28。 微量注射抗p28对蛋白质功能失活的影响 抗体和反义DNA将尝试调查一种 P28的活体作用。

Cell cycle progression is a tightly regulated event, the deregulation of which is a hallmark of cancer. Eukaryotic cell cycles are controlled by the temporal association of a cyclin dependent kinase (cdk) with a cyclin partner, leading to the activation of these complexes and the subsequent phosphorylation of critical substrates. The mammalian D-type cyclins and their cdk partners, cdk4 and cdk6, are important regulators of G1 phase progression; little is known about how these cdk/cyclin complexes are regulated, however. This proposal describes the molecular cloning and biochemical characterization of a novel approximate 28 kDa protein (p28) found in cdk6 immunoprecipitates containing D-type cyclins isolated from primary human T- cells in early G1 phase. Curiously, p28 immunoreacts with antibodies generated against p27KIP1, a recently identified cdk inhibitor, yet is distinct from p27KIP1. These findings raise the intriguing possibility that p28 represents a novel cdk inhibitor and that its association with cdk6/ cyclin D complexes has an important regulatory function for G1 phase control. Knowing the cDNA sequence of p28 will allow its expression and association with various cdk/ cyclin complexes as a function of the cell cycle to be analyzed. The possibility that p28 affects the kinase activity of cdk6/ cyclin D complexes or other cdk/ cyclin complexes will be investigated. The minimal domains on p28 required for p28 association with and activity towards cdk/ cyclin complexes will be mapped. Lastly, overexpression of p28 by transient transfection and functional inactivation of the protein by microinjection of anti-p28 antibodies and antisense DNA will be attempted to investigate an in vivo role for p28.