Genetic Analysis of Ras and G Protein Function

Ras 和 G 蛋白功能的遗传分析

• 批准号: 6932013
• 负责人: LARRY FEIG
• 金额: $ 37.25万
• 依托单位: TUFTS UNIVERSITY BOSTON
• 依托单位国家: 美国
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-04-15 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6932013
• 关键词: G protein; binding proteins; biological signal transduction; breast neoplasms; calcium channel; calcium ion; calmodulin; carcinogenesis; cell cell interaction; gene expression; gene mutation; genetic regulation; genetic screening; genetically modified animals; guanine nucleotide binding protein; guanine nucleotide exchange factors; guanosinetriphosphatases; laboratory mouse; neoplasm /cancer genetics; neurons; nucleic acid sequence; oncogenes; protein structure function; tissue /cell culture

DESCRIPTION (provided by applicant): The overall goal of this proposal is to gain a better understanding of how Ras proteins couple extracellular signals to intracellular signaling pathways in normal and disease states. The Ras superfamily of GTPases participate in the regulation of a wide variety of cellular processes by functioning as molecular switches that cycle between the active GTP-bound and inactive GTP-bound states. A key step in how Ras protein function is modulated in cells is by their activation by a family of guanine nucleotide exchange factors (GEFs), whose role is to respond to a specific extracellular signals by promoting the exchange of GTP for GDP bound to Ras proteins. This proposal will investigate how the Ras-GRF family of GEFs contribute to the control signaling pathways mediated by the Ras family of GTPases. Ras-GRF1 and Ras-GRF2 each have two GEF domains, one used to activate the Ras proto-oncogenes and another used to activate the Rac GTPase. Calcium/calmodulin binding regulates the ability of Ras-GRFs to activate Ras and Rac. Ras-GRFs can also be stimulated by phosphorylation. Both Ras-GRF proteins are expressed predominantly, but not exclusively in neurons. This proposal will use both genetic and biochemical approaches to focus on three major areas of study. The first is to reveal how the Ras-GRF family contributes to receptor/ calcium channel signaling in neurons by exploiting our recently derived mouse strains that lack Ras-GRF1, Ras-GRF2 or both Ras-GRFs. The second is to reveal how two classes of newly identified Ras-GRF binding proteins contribute to Ras GTPase regulation. These binding proteins include IB1 and IB2 (scaffolds for components of the Jnk and p38 MAP kinase cascades, respectively) and spinophilin (a scaffold for the p70 S6 kinase and protein phosphatase 1). Finally, the third goal is to investigate the biological function of the newly identified Ras-GRF1 target, R-Ras, in oncogenesis. These studies will exploit our recent finding that constitutively activated R-Ras is a potent activator of estrogen independent proliferation in MCF-7 breast cancer cell lines.

描述（由申请人提供）：该提案的总体目标是更好地了解RAS蛋白如何将细胞外信号与正常和疾病状态中的细胞内信号通路息息。 GTPases的RAS超家族通过用作分子开关来调节各种细胞过程，该分子开关循环在活动的GTP结合和不活跃的GTP结合状态之间循环。 RAS蛋白功能在细胞中如何调节的关键步骤是通过鸟嘌呤核苷酸交换因子（GEF）的激活，其作用是通过促进与RAS蛋白的GDP的GDP交换来响应特定的细胞外信号。该建议将调查GEF的RAS-GRF家族如何促进GTPases RAS家族介导的控制信号通路。 RAS-GRF1和RAS-GRF2每个都有两个GEF结构域，一个用于激活RAS原始癌基因，另一个用于激活RAC GTPase。钙/钙调蛋白结合调节RAS-GRF激活RAS和RAC的能力。 RAS-GRF也可以通过磷酸化刺激。两种RAS-GRF蛋白主要表达，但不仅在神经元中表达。该建议将使用遗传和生化方法来关注三个主要研究领域。首先是揭示RAS-GRF家族如何通过利用缺乏RAS-GRF1，RAS-GRF2或两个RAS-GRF的最近衍生的小鼠菌株来促进神经元中的受体/钙通道信号传导。第二个是揭示两类新鉴定的Ras-GRF结合蛋白如何促进RAS GTPase调节。这些结合蛋白包括IB1和IB2（分别用于JNK和P38 MAP激酶级联反应的支架）和旋转蛋白（P70 S6激酶和蛋白质磷酸酶1的支架）。最后，第三个目标是研究新鉴定的Ras-Grf1靶标R-RAS在肿瘤发生中的生物学功能。这些研究将利用我们最近的发现，即组成型激活的R-RAS是MCF-7乳腺癌细胞系中雌激素独立增殖的有效激活因子。