CELLULAR TARGETS OF POLYMAVIRUS TRANSFORMING PROTEINS

描述：对特定结合的细胞蛋白质的研究 事实证明，乳头状病毒的肿瘤抗原对我们的 对人类癌症的理解，对信号产生重要的见解 在癌症中起作用的转导途径。蛋白磷酸酶2A (PP2A)和14-3-3蛋白是一类高度保守的蛋白质，广泛存在于 真核生物。已知它们参与了细胞的控制 并且是乳头状病毒癌基因的细胞靶点， 多瘤病毒中间肿瘤抗原(MT)，与其形成稳定的 复合体。这项提议的长期目标是理解 (S)PP2A和14-3-3蛋白在MT功能中的作用和调节， 尤其是MT介导的转化。该方法将包括三个方面：1) 第一，直接研究PP2A活性在 PP2A/MT/pp60c-src复合体的形成和功能、MT和pp60c-src 与催化失活的PP2A点突变相关的将被分析 从生化和功能上来确定类型、位置和 新改装的功能重要性。2)第二，因为 理解MT对PP2A的调控需要进一步描述正常 PP2A调节，三个新的PP2A相关蛋白很可能是 参与PP2A功能，也可能有助于阐明MT在 将对PP2A进行鉴定和/或克隆，并进行初步鉴定。每一个 这些蛋白质将通过免疫亲和纯化得到纯化， 微测序，克隆，如果是新的，并用生化和 关于他们参与PP2A和MT功能的功能。3) 第三，确定14-3-3蛋白是否与致癌有关 MT的转化，可能是通过影响其他蛋白质的结合 利用MT，将分离出与14-3-3蛋白结合缺陷的MT突变体 并分析了与细胞蛋白和In形成的络合物 变形分析。

DESCRIPTION: The study of cellular proteins that are specifically bound by the tumor antigens of papovaviruses is proving increasingly important to our understanding of human cancer, yielding important insights into signal transduction pathways that play a role in cancer. Protein phosphatase 2A (PP2A) and 14-3-3 proteins are highly conserved proteins ubiquitous in eukaryotes. They are known to be involved in the control of cell proliferation and are cellular targets of the papovavirus oncogene, polyomavirus middle tumor antigen (MT), with which they form stable complexes. The long range goal of this proposal is to understand both the role(s) and regulation of PP2A and 14-3-3 proteins in MT functions, especially MT-mediated transformation. The approach will be threefold: 1) First, to directly investigate the role of PP2A activity in PP2A/MT/pp60c-src complex formation and function, MT and pp60c-src associated with catalytically inactive PP2A point mutants will be analyzed biochemically and functionally to determine the type, location, and functional importance of novel modifications. 2) Second, because understanding MT regulation of PP2A requires further delineation of normal PP2A regulation, three novel PP2A-associated proteins that are likely to be involved in PP2A function and are also likely to shed light on MT effects on PP2A will be identified and/or cloned and initially characterized. Each of these proteins will be purified by immunoaffinity purification, microsequenced, cloned if novel, and characterized biochemically and functionally in regard to their involvement in PP2A and MT functions. 3) Third, to determine if 14-3-3 proteins contribute to oncogenic transformation by MT, perhaps by affecting association of other proteins with MT, MT mutants defective in binding 14-3-3 proteins will be isolated and analyzed for complex formation with cellular proteins and in transformation assays.