Role of Vav family proteins in cell signaling and cancer

Vav 家族蛋白在细胞信号传导和癌症中的作用

• 批准号: 6968526
• 负责人: XOSE R BUSTELO
• 金额: $ 19.44万
• 依托单位: UNIVERSITY OF SALAMANCA
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-06-01 至 2010-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6968526
• 关键词: X ray crystallography; biological signal transduction; cell proliferation; conformation; electron microscopy; expression cloning; gene targeting; guanine nucleotide binding protein; guanosinetriphosphatases; intermolecular interaction; laboratory mouse; neoplastic transformation; oncogenes; oncoproteins; phosphoproteins; phosphorylation; protein structure function; proteomics; protooncogene; site directed mutagenesis

DESCRIPTION (provided by applicant): The Vav family is a group of oncoproteins with three representatives in vertebrates (Vav, Vav2, and Vav3) and single members in invertebrates. These proteins catalyze the exchange of nucleotides on GTP-binding proteins of the Rho/Rac family, thereby facilitating the transition of these GTPases from their inactive (GDP-bound) to their active (GTP-bound) state. The enzyme activity of Vav proteins is tightly regulated during signal transduction by direct tyrosine phosphorylation. As a consequence, they only become activated when phosphorylated by upstream receptors with intrinsic or associated tyrosine kinase activity. Several lines of evidence demonstrate that the function of Vav proteins is crucial for both developmental and mitogenic processes. Thus, the deletion of vav and vav2 genes by homologous recombination results in defective maturation of lymphocyte lineages and lack of proper antigenic responses. Furthermore, the ectopic expression of gain-of-function mutants of Vav and Vav2 induces high levels of cellular transformation in rodent fibroblasts. Finally, recent results have implicated the Vav pathway in the pathogenic cycle of human lymphotropic viruses such as HIV, HTLV, and gamma-herpesviruses. The long-term objective of our laboratory is to achieve a comprehensive characterization of this protein family at the biochemical, structural, cellular, and organism level. To achieve this objective, the following studies will be carried out. In Aim 1, structural biology and biochemical techniques will be used to visualize the conformational changes underwent by these proteins upon binding to upstream regulators and GTPase substrates. In Aim 2, proteomic and expression cloning approaches will be used to reveal regulatory mechanisms of Vav proteins based on both posttranslational modifications and interactions with other intracellular molecules. In Aim 3, signaling techniques will be utilized to dissect new crosstalk and feedback mechanisms operating in the Vav pathway. In Aim 4, available knockout mice for the three vav family genes will be used to study the role of Vav proteins in cell signaling and physiological processes that, when deregulated, contribute to human disease. Taken together, these studies should provide a unified vision of the modus operandi of Vav proteins during signal transduction and, at the same time, supply valuable information for the design of pharmacological tools that could aid in the manipulation of Vav family-dependent biological processes in the future.

描述（由申请人提供）：Vav 家族是一组癌蛋白，在脊椎动物中具有三个代表（Vav、Vav2 和 Vav3），在无脊椎动物中具有单一成员。这些蛋白催化 Rho/Rac 家族 GTP 结合蛋白上的核苷酸交换，从而促进这些 GTP 酶从非活性（GDP 结合）状态转变为活性（GTP 结合）状态。 Vav 蛋白的酶活性在信号转导过程中通过直接酪氨酸磷酸化受到严格调节。因此，它们仅在被具有内在或相关酪氨酸激酶活性的上游受体磷酸化时才会被激活。多项证据表明 Vav 蛋白的功能对于发育和有丝分裂过程至关重要。因此，通过同源重组删除vav和vav2基因会导致淋巴细胞谱系的成熟缺陷和缺乏适当的抗原反应。此外，Vav 和 Vav2 功能获得突变体的异位表达可诱导啮齿动物成纤维细胞发生高水平的细胞转化。最后，最近的结果表明 Vav 通路与人类嗜淋巴细胞病毒（例如 HIV、HTLV 和 γ-疱疹病毒）的致病周期有关。我们实验室的长期目标是在生化、结构、细胞和有机体水平上实现该蛋白质家族的全面表征。为实现这一目标，将开展以下研究。在目标 1 中，将使用结构生物学和生化技术来可视化这些蛋白质在与上游调节因子和 GTP 底物结合后所经历的构象变化。在目标 2 中，蛋白质组学和表达克隆方法将用于揭示基于翻译后修饰和与其他细胞内分子相互作用的 Vav 蛋白的调节机制。在目标 3 中，将利用信号技术来剖析 Vav 通路中运行的新串扰和反馈机制。 在目标 4 中，将使用三种 vav 家族基因的现有敲除小鼠来研究 Vav 蛋白在细胞信号传导和生理过程中的作用，这些信号和生理过程在失调时会导致人类疾病。 总而言之，这些研究应该为信号转导过程中 Vav 蛋白的操作方式提供统一的视角，同时为药理学工具的设计提供有价值的信息，这些工具可以帮助将来操纵 Vav 家族依赖性生物过程。