CELLULAR TARGETS OF POLYMAVIRUS TRANSFORMING PROTEINS

描述：研究细胞蛋白质的特异性结合， 乳多空病毒的肿瘤抗原对我们的研究越来越重要， 了解人类癌症，产生重要的见解信号 在癌症中发挥作用的转导途径。 蛋白磷酸酶2A （PP 2A）和14-3-3蛋白是在哺乳动物中普遍存在的高度保守蛋白。 真核生物 已知它们参与细胞的控制， 增殖并且是乳多空病毒癌基因的细胞靶， 多瘤病毒中间肿瘤抗原（MT），它们与之形成稳定的 配合物 本提案的长期目标是了解 PP 2A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） 首先，直接研究PP 2A活性在 PP 2A/MT/pp 60 c-src复合物的形成和功能，MT和pp 60 c-src 将分析与催化失活的PP 2A点突变体相关的 生物化学和功能，以确定类型，位置， 新修饰的功能重要性。 2)二是因为 了解PP 2A的MT调节需要进一步描述正常的 PP 2A调节，三种新的PP 2A相关蛋白，可能是 参与PP 2A功能，也可能揭示MT对 PP 2A将被鉴定和/或克隆并初步表征。 中的每 这些蛋白质将通过免疫亲和纯化来纯化， 微测序，如果是新的，则克隆，并进行生物化学表征， 就其参与PP 2A和MT功能而言，在功能上是不同的。 第三章 第三，为了确定14-3-3蛋白是否有助于致癌， 通过MT转化，可能通过影响其他蛋白质的结合 使用MT，将分离出在结合14-3-3蛋白方面有缺陷的MT突变体 并分析与细胞蛋白质的复合物形成， 转化测定。

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.