G protein signal integration by multifunctional proteins

多功能蛋白的 G 蛋白信号整合

• 批准号: 6878081
• 负责人: T KENDALL HARDEN
• 金额: $ 124.42万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-04-10 至 2007-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6878081
• 关键词: G protein; biological signal transduction; guanosinetriphosphatase activating protein; protein protein interaction

DESCRIPTION (provided by applicant): G protein-mediated signaling underlies the action of many growth factors, hormones, and neurotransmitters. Although initially conceived as linear and unidirectional, many G protein-related cell signaling pathways now are known to converge (and diverge) at many levels. For example, members of the large family of RGS proteins exhibit multiple biochemical activities in addition to their signature capacity to promote G-alpha-mediated GTP hydrolysis. This program project (PPG) applies a multidisciplinary approach to gain mechanistic and structural insight into important examples of multifunctional proteins in G protein signaling. We have assembled investigators with expertise in cancer biology (Der), in signaling in yeast (Dohlman), and in the molecular pharmacology/biochemistry (Harden), molecular biology/bioinformatics (Siderovski), and structure (Sondek) of G protein signaling. A Protein Core will play a central role in the PPG by facilitating high-throughput cloning, expression, purification, and biophysical characterization of proteins. The mechanism(s) of R7-family RGS proteins in "upstream" regulation of receptor/G protein interaction and cross-talk among heterotrimeric G proteins will be determined in Project I through studies with mammalian and C. elegans proteins. The multifunctional nature of the newly identified PLC-epsilon isozyme will be delineated in Project II through studies identifying interactors for the N-terminal RasGEF and C-terminal Ras-association domains, the role of PLC-epsilon in Ras-promoted cell transformation, and the domain(s) in PLC-epsilon that interacts with G-alpha-subunits. Project III will focus on the yeast protein Sst2, which was the first RGS protein discovered, and which contains an N-terminal DEP domain of unknown function also found in the mammalian R7-family RGS proteins studied in Projects I and IV. Yeast two-hybrid screens have identified proteins that bind the Sst2 N-terminal domain, and which activate the stress response signal. The domains of Sst2 responsible for G protein effector activity will be defined, as will the mechanism(s) of stress response signaling. Project IV will establish the structural basis for several functional interactions mediating cross-talk in G protein signaling by solving the structures of the beta5-R7 dimer and the GoLoco domain of R12-family RGS proteins, which has been shown to inhibit GDP release by G-alpha-i-subunits. This PPG will provide major new mechanistic insights into the molecular complexities that function across G protein signaling pathways and should illuminate new drug targets within fundamental processes that underlie diseases as diverse as cancer, heart disease, and mental disorders.

描述(申请人提供)：G蛋白介导的信号转导是 许多生长因子、激素和神经递质的作用。虽然 最初设想为线性和单向的，许多G蛋白相关的细胞 现在已知信号通路在许多水平上汇聚(和发散)。为 例如，RGS蛋白大家族的成员表现出多个 生化活动除了其招牌能力外，还能促进 G-α介导的GTP水解酶。此计划项目(PPG)适用于 多学科方法以获得机械和结构上的洞察 多功能蛋白在G蛋白信号转导中的重要例子。我们有 召集具有癌症生物学(Der)专业知识的研究人员，发出信号 酵母菌(Dohlman)和分子药理/生物化学(Harden)， 分子生物学/生物信息学(Siderovski)和G的结构(Sondek) 蛋白质信号。蛋白质核心将通过以下方式在PPG中发挥核心作用 促进高通量克隆、表达、纯化和生物物理 蛋白质的特性。R7家族RGS蛋白的作用机制(S) 受体/G蛋白相互作用和串扰的“上游”调节 异三聚体G蛋白将在项目I中通过与 哺乳动物和线虫蛋白。新车的多功能特性 已鉴定的PLC-epsilon同工酶将通过研究在项目II中划定 识别N端Rasgef和C-端的相互作用因子 RAS结合结构域、PLC-epsilon在RAS促进的细胞中的作用 转换，以及与之交互的PLC-epsilon中的域(S) G-α-亚基。项目III将专注于酵母蛋白Sst2，它曾是 第一个发现的含有N-末端DEP结构域的RGS蛋白 在所研究的哺乳动物R7家族RGS蛋白中也发现了未知的功能 在项目I和IV中，酵母双杂交筛选已经识别出 结合Sst2的N-末端结构域，并激活应激反应信号。 负责G蛋白效应器活性的Sst2结构域将是 定义，以及应激反应信号的机制(S)。项目IV将 为调解几种功能相互作用建立结构基础 通过解决Beta5-R7的结构来解决G蛋白信号中的串扰 二聚体和R12家族RGS蛋白的GoLoco结构域，已被证明 抑制G-α-I亚基对GDP的释放。这个PPG将提供重大的新的 对G中起作用的分子复杂性的机械论见解 蛋白质信号通路，并应照亮新的药物靶点 癌症、心脏等各种疾病的基本过程 疾病和精神障碍。