REGULATION HETEROTRIMERIC G PROTEINS

调节异源三聚体 G 蛋白

• 批准号: 6650300
• 负责人: TOHRU KOZASA
• 金额: $ 22.12万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-01 至 2005-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6650300
• 关键词: G protein; acetylcholine; affinity chromatography; biological signal transduction; enzyme activity; guanine nucleotide binding protein; guanine nucleotide exchange factors; guanosinetriphosphatase activating protein; guanosinetriphosphatases; molecular cloning; neurogenesis; neuronal guidance; phosphorylation; protein structure function; tissue /cell culture; yeast two hybrid system

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.

描述：（申请人的摘要改编）异三聚体G蛋白 将各种信号从膜结合的受体转移到细胞内 效应子。低分子量GTPases控制的Rho家族的成员 肌动蛋白细胞骨架的组织，并参与多种 细胞功能。该提议的目的是了解 异位三聚体G对Rho家族GTPase调节的机理 蛋白质介导的信号通路。在异三聚体G蛋白中，galpha12 和galpha13 -participate在细胞转化和胚胎发育中，以及 Rho似乎参与了他们的信号通路。因此，直接 该提议的目标是了解调节的生化机制 Galpha12和Galpha13的Rho家族成员的活动。 Rho Family GTPases 被鸟嘌呤核苷酸交换因子（GEFS）激活。我们有 证明Galpha12和Galpha13与活动相互作用并调节 小说的Rho GEF，P115。 Galpha13刺激P115的Rho GEF活性。在 对比度，Galpha12抑制了Galpha13对P115的激活。此外， Rhogef充当Galpha12和 Galpha13。 P115rhogef的调节将进一步详细表征。 使用Galpha的选定突变体将改善差距测定 蛋白质和负责间隙活性的P115领域将定义。 另外，P115的分子机理由 Galpha12和Gaalpha13将进行研究。 Galpha12可以在体内激活Rho。 但是，galpha12不会刺激P115的RhoGEF活性。我们会这样 尝试找到由Galpha12激活的Rhogef 使用固定的Galpha12色谱法。生理意义的 galpha12和galpha13对Rhogef活性的调节也将是 在体内进行了调查。轴突中G12，G13-Rhogef途径的参与 增长和指导将被表征。