REGULATION HETEROTRIMERIC G PROTEINS

描述：(摘自申请者摘要)异三聚体G蛋白 将多种信号从膜结合受体传递到细胞内 效应器。Rho家族低分子量GTP酶家族成员的控制 肌动蛋白细胞骨架的组织，并参与多种 细胞功能。这项建议的目的是了解 异源三聚体G对Rho家族GTP酶的调节机制 蛋白质介导的信号通路。在异源三聚体G蛋白中，Galpha12 和Galpha13参与细胞转化和胚胎发育，以及 Rho似乎参与了它们的信号通路。因此，直接的 这项建议的目标是了解生物化学机制的调节 由Galpha12和Galpha13表示的Rho家族成员的活动。Rho家族GTP酶 被鸟嘌呤核苷酸交换因子(GEF)激活。我们有 证明Galpha12和Galpha13与该活动相互作用和调节 一部小说《罗伊环境基金》，第115页。Galpha13刺激p115的Rho环境生长因子活性。在……里面 相反，Galpha12抑制Galpha13对p115的激活。此外， Rhogef作为GTP酶激活蛋白(GAP)对Galpha12和 Galpha13.对p115Rhogef的调控将进一步详细描述。 GAP分析将使用所选的Galpha突变体进行改进 蛋白质，以及负责GAP活性的p115结构域将被定义。 此外，p115的差异调控的分子机制还包括 将对Galpha12和Gaalpha13进行调查。Galpha12可在体内激活Rho。 然而，Galpha12不能刺激p115的Rhogef活性。因此，我们将 尝试查找由Galpha12通过关联性激活的Rhogef 使用固定化Galpha12进行层析。的生理学意义 Galpha12和Galpha13对RhoGlobal活性的调节也将是 活体研究。G12、G13-Rhogef通路在轴突中的作用 将以增长和指导为特征。

DESCRIPTION: (Adaptedfrom Applicant's Abstract) Heterotrimeric G proteins transduce a variety of signals from membrane-bound receptors to intracellular effectors. Members of the Rho family of low-molecular-weight GTPases control the organization of the actin cytoskeleton and are involved in a variety of cellular functions. The objective of this proposal is to understand the mechanism of regulation of Rho family GTPases by heterotrimeric G protein-mediated signaling pathways. Among heterotrimeric G proteins, Galpha12 and Galpha13participate in cell transformation and embryonic development, and Rho appears to be involved in their signaling pathways. Thus, the immediate goal of this proposal is to understand biochemical mechanisms of regulation of the activity of Rho family members by Galpha12 and Galpha13. Rho family GTPases are activated by guanine nucleotide exchange factors (GEFs). We have demonstrated that Galpha12 and Galpha13 interact with and regulate the activity of a novel Rho GEF, p115. Galpha13 stimulates the Rho GEF activity of p115. In contrast, Galpha12 inhibits activiation of p115 by Galpha13. Furthermore, RhoGEF acts as a GTPase activating protein (GAP) for both Galpha12 and Galpha13. The regulation of p115RhoGEF will be further characterized in detail. The GAP assay will be improved using the selected mutants of the Galpha proteins, and the domain of p115 responsible for GAP activity will be defined. In addition, the molecular mechanism of differential regulation of p115 by Galpha12 and Gaalpha13 will be investigated. Galpha12 can activate Rho in vivo. However, Galpha12 does not stimulate the RhoGEF activity of p115. We will thus attempt to find a RhoGEF that is activated by Galpha12 by affinity chromatography using immobilized Galpha12. The physiological significance of regulation of RhoGEF activity by Galpha12 and Galpha13 will also be investigated in vivo. The involvement of the G12, G13-RhoGEF pathways in axonal growth and guidance will be characterized.