Regulation and Functin of the p190 RhoGAPs

p190 RhoGAP 的调节和功能

• 批准号: 6863700
• 负责人: JEFFREY E SETTLEMAN
• 金额: $ 36.34万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-01-01 至 2007-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6863700
• 关键词: Drosophilidae; actins; adhesions; biological signal transduction; cell differentiation; cell growth regulation; developmental neurobiology; enzyme activity; gene targeting; genetically modified animals; guanine nucleotide binding protein; guanosinetriphosphatase activating protein; guanosinetriphosphatases; laboratory mouse; neoplasm /cancer genetics; neuronal guidance; protein localization; protein structure function; tissue /cell culture; transfection

Abnormal regulation of the Ras and Rho GTPases is associated with oncogenesis. Among the key regulators of these GTPases are the GTPase activating proteins (GAPs). The GAPs act, biochemically, as potent stimulators of the weak intrinsic GTP hydrolyzing activity of small GTPases, thereby inactivating them. However, the biological function of these numerous and ubiquitous regulatory proteins is poorly understood. To determine the precise signaling mechanism and functional role for GAPs, mouse knockouts corresponding to each of two closely related RhoGAPs, known as the p190 RhoGAPs, have been generated. Each of the knockout mice exhibits a perinatal lethal phenotype, and embryo- derived cells and tissues will be used to examine the signaling role and biological requirements for these proteins. The function of the p190 RhoGAPs will be examined at the molecular, cellular, and organismal levels. For p190 RhoGAP, the hypothesis will be tested that this protein mediates an adhesion signaling pathway via the Src and PKC kinases that directs Rho-mediated actin reorganization during neural development. For p190-B RhoGAP, the hypothesis will be tested that this protein modulates Rho activity in a pathway downstream of insulin that directs CREB-dependent cell size regulation and differentiation in nervous and non-nervous tissues. The nature of an observed partial functional redundancy between these two proteins in embryonic development will be examined by inter-crossing the two knockout lines. In addition, a closely related Drosophila homologue of the p190 RhoGAPs has been identified, and loss-of- function mutations of this gene will be generated to examine the role of the protein in a genetically tractable model system. The proposed studies are expected to substantially advance the current understanding of p190 RhoGAP function, and the broad objective of the work is to gain insight into the general biological and signaling functions of the GAPs. This is an important step toward establishing an accurate picture of the regulatory mechanisms for small GTPases in vivo, and the nature of their dysregulation in human cancers.

Ras 和 Rho GTP 酶的异常调节与肿瘤发生有关。 GTP 酶激活蛋白 (GAP) 是这些 GTP 酶的关键调节因子之一。 从生化角度来看，GAP 作为小 GTP 酶弱内在 GTP 水解活性的有效刺激剂，从而使它们失活。然而，人们对这些数量众多且普遍存在的调节蛋白的生物学功能知之甚少。 为了确定 GAP 的精确信号传导机制和功能作用，已经生成了与两个密切相关的 RhoGAP（称为 p190 RhoGAP）相对应的小鼠基因敲除。 每只基因敲除小鼠都表现出围产期致死表型，胚胎来源的细胞和组织将用于检查这些蛋白质的信号传导作用和生物学需求。 p190 RhoGAP 的功能将在分子、细胞和生物体水平上进行检查。 对于 p190 RhoGAP，我们将测试以下假设：该蛋白通过 Src 和 PKC 激酶介导粘附信号通路，从而在神经发育过程中指导 Rho 介导的肌动蛋白重组。 对于 p190-B RhoGAP，将测试以下假设：该蛋白调节胰岛素下游通路中的 Rho 活性，从而指导神经和非神经组织中 CREB ​​依赖性细胞大小调节和分化。 胚胎发育中这两种蛋白质之间观察到的部分功能冗余的性质将通过两个敲除系的交叉进行检查。 此外，p190 RhoGAP 的果蝇密切相关同源物已被鉴定，并且将产生该基因的功能丧失突变，以检查该蛋白质在遗传易处理模型系统中的作用。 拟议的研究预计将大大推进目前对 p190 RhoGAP 功能的理解，并且该工作的广泛目标是深入了解 GAP 的一般生物学和信号传导功能。 这是朝着准确了解小 GTP 酶体内调节机制及其在人类癌症中失调的性质迈出的重要一步。