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。蛋白质磷酸化是广泛使用的实现信号整合和生物协调的调节机制之一。我们一直在研究特定蛋白质磷酸化事件在控制细胞形态、粘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）作为信号整合器的关键作用，其被各种细胞内激酶磷酸化似乎对其在各种细胞过程中的作用至关重要。我们的总体目标是清楚地了解 RhoGAP 对 Rho 介导的细胞过程的调节，本文提出的研究重点是解决 p190 RhoGAP 磷酸化在上游调节信号整合中的作用。提出以下目标： 1) 建立 PKC 介导的 p190A RhoGAP 磷酸化的调节功能。 2) 确定p190A在极化细胞迁移中的磷酸调节作用。 3) 确定磷酸化调节蛋白与 p190 FF 结构域相互作用的功能作用。 4) 建立p190B RhoGAP在细胞粘附IGF-1信号传导中的调节。这 4 个目标反映了大量初步数据，这些数据指出了 p190 GAP 在调节各种细胞生物和发育过程中的关键磷酸化事件。我们已经生成了该分析所需的绝大多数试剂，预计将揭示这些 GAP 作为信号积分器或调节 Rho 依赖性细胞过程（包括细胞迁移）的“巧合传感器”的作用的大量新见解。细胞迁移是人类癌症中的一项重要细胞活动，其在转移（致瘤过程中最致命的方面）中的作用已明确确定。通过识别影响细胞迁移的调节机制，最终应该有可能开发出新的治疗策略来预防或控制癌症转移。 公共健康相关性：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，即各种细胞内蛋白质如何整合各种细胞外刺激来正确“指导”细胞做出适当反应？通过增强我们对癌细胞如何对其环境做出反应的理解，我们也许能够制定策略来破坏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.