Signal integration via phospho-regulation of RhoGAPs

描述(由申请人提供)：不同细胞信号的整合对于几乎所有生物过程的精确空间和时间协调至关重要。在实现信号整合和生物协调的广泛使用的调控机制中，蛋白质磷酸化是其中之一。我们一直在研究特定的蛋白质磷酸化事件在控制细胞形态、黏附和迁移过程中的作用--这些过程受到Rho GTP酶的严格调控。这些研究揭示了p190 Rho GTP酶激活蛋白(Gap；p190A和p190B)作为信号整合蛋白的关键作用，其被各种细胞内激酶的磷酸化似乎是其在各种细胞过程中发挥作用的关键。我们的广泛目标是对RhoGAP对Rho介导的细胞过程的调控有一个明确的了解，这里提出的研究的重点是解决p190 RhoGAP磷酸化在整合上游调控信号中的作用。1)建立PKC介导的p190A RhoGAP磷酸化的调控功能。2)确定p190A在极化细胞迁移中的磷酸化调控作用。3)确定磷酸化调控蛋白与p190 Ff结构域相互作用的功能作用。4)建立p190B RhoGAP在IGF-1信号转导细胞黏附中的调节作用。这4个目标反映了大量的初步数据，表明这些关键的磷酸化事件在p190缺口在调节各种细胞生物学和发育过程中的作用。我们已经产生了这项分析所需的绝大多数试剂，这有望揭示这些间隙作为信号整合者或调控依赖于Rho的细胞过程(包括细胞迁移)的“符合传感器”所扮演的角色。在人类癌症的背景下，细胞迁移是一种重要的细胞活动，它在肿瘤发生过程中最致命的方面-转移中的作用已经明确。通过确定影响细胞迁移的调控机制，最终应该有可能开发出新的治疗策略来预防或管理癌症转移。 公共卫生相关性：拟议的研究解决了所有正常细胞和癌细胞生物学中的一个基本问题，即各种细胞内蛋白如何整合各种细胞外刺激，以适当地“指示”细胞做出适当的反应？通过加强我们对癌细胞如何对其环境做出反应的了解，我们可能能够制定策略来扰乱这些细胞中导致其加速生长和转移扩散的恶性特性的过程。

DESCRIPTION (provided by applicant): The integration of diverse cellular signals is critical to the precise spatial and temporal coordination of virtually all biological processes. Among the widely used regulatory mechanisms to achieve signal integration and biological coordination is protein phosphorylation. We have been investigating the role of specific protein phosphorylation events in controlling cell morphology, adhesion, and migration- processes that are stringently regulated by the Rho GTPases. These studies have revealed a critical role for the p190 Rho GTPase activating proteins (GAPs; p190A and p190B) as signal integrators whose phosphorylation by various intracellular kinases appears to be critical to its role in a variety of cellular processes. Our broad objective is to develop a clear understanding of the regulation of Rho- mediated cellular processes by the RhoGAPs, and the focus of the studies proposed here is to address the role of p190 RhoGAP phosphorylation in the integration of upstream regulatory signals. The following Aims are proposed: 1) To establish the regulatory function of PKC-mediated phosphorylation of p190A RhoGAP. 2) To establish a role for phospho-regulation of p190A in polarized cell migration. 3) To determine the functional role of phosphorylation-regulated protein interactions with the p190 FF domains. 4) To establish the regulation of p190B RhoGAP in IGF-1 signaling in cell adhesion. These 4 Aims reflect a large body of preliminary data that points to these critical phosphorylation events in the role of the p190 GAPs in regulating a variety of cell biological and developmental processes. We have generated the vast majority of reagents required for this analysis, which is expected to reveal substantial new insights into the role of these GAPs as signal integrators or "coincidence sensors" that regulate Rho-dependent cellular processes, including cell migration. Cell migration is an important cellular activity in the context of human cancers, where its role in metastasis, the most lethal aspect of the tumorigenic process, has been clearly established. By identifying regulatory mechanisms that affect cell migration, it should eventually be possible to develop novel therapeutic strategies to prevent or manage cancer metastasis. PUBLIC HEALTH RELEVANCE: The proposed studies address a fundamental issue in the biology of all normal and cancer cells, namely how do the various intracellular proteins integrate a variety of extracellular stimuli to properly "instruct" the cell to respond appropriately? By enhancing our understanding of how cancer cells respond to their environment, we may be able to develop strategies to disrupt the processes in these cells that contribute to their malignant properties of accelerated growth and metastatic spread.