RGS14 integration of Gi/o and rap1/2 signaling pathways

超出所提供的空间。神经递质和激素依赖G蛋白对靶细胞发挥作用。相反，生长因子酪氨酸激酶受体招募一系列相关的信号蛋白，包括ras样GTPases来调节细胞生长和分化。最近令人信服的证据表明，其他新的信号蛋白，包括G_的某些调节因子。蛋白质信号（RGS蛋白）在许多水平上整合了G蛋白和ras超家族导向的途径。RGS蛋白是一种高度多样化的多功能蛋白，可直接与G蛋白结合并调节其功能。RGSI4包含的结构域（RGS， GoLoco和RID结构域），我们和其他人已经证明与活性Gcd/o-GTP （RGS结构域），非活性Gcd/o-GDP （GoLoco结构域）以及与ras样GTPases rapl和rap2 （RID结构域）相互作用。宿主细胞rapl/2通路的激活刺激MAPK/Erk激酶信号传导和神经元分化。RGS14作为Gai和Gao信号的双重调节因子的作用尚不清楚。此外，RGS14、Gcd/o和rapl/2如何相互作用以调节彼此的功能，以及调节这些相互作用和相关细胞反应的细胞机制尚不清楚。我们的初步研究表明RGS14被参与G蛋白和rap信号传导的激酶磷酸化。我们的假设是RGS14是G蛋白（Ged/o）和rap定向信号通路的整合者，刺激启动磷酸化调节RGS14与G_和rap的相互作用、其亚细胞定位和信号功能。使用现代分子、细胞和生化方法，具体目标将是：1。确定RGS I4作为受体和细胞膜上的G(o)和G(o)信号的双功能调节剂的作用。2. 确定宿主B35细胞中调控RGS - 14膜募集和附着、亚细胞定位以及与mChoR、Gczi/o和rapl/2的a-关联的细胞和生化机制。3. 明确细胞中调控RGS14磷酸化的细胞机制，以及体外RGS14与mChoR/Gi/o和rapt/2的相互作用以及B35细胞中相关信号通路中磷酸化的作用。4. 确定B35细胞中过表达RGSI4或消除天然RGS14对mChoR/Gi/o和rapl/2定向信号事件和细胞反应的影响。影响：这些研究将确定以前未被认识的RGS蛋白的细胞信号作用，并提供关于G蛋白信号通路和rap/ map激酶信号通路之间串扰的新机制的重要信息。这些研究结果将阐明我们对G蛋白/RGS蛋白信号传导复杂性的理解，并确定治疗干预的潜在新靶点。PERFORMANCESITE ( ======================================== 节结束 ===========================================

EXCEED THE SPACE PROVIDED. Neurotransmitters and hormones rely upon G proteins to exert their effects on target cells. In contrast, growth factor tyrosine kinase receptors recruit a cascade of linked signaling proteins including ras-like GTPases to regulate cell growth and differentiation. Recent compelling evidence indicates that additional novel signaling proteins, including certain regulators of G_. protein signaling (RGS proteins) integrate G protein and ras superfamily-directed pathways at many levels. RGS proteins are highly diverse, multifunctional proteins that bind directly to G proteins to regulate their functions. RGSI4 contains domains (RGS, GoLoco and RID domains) that we and others have shown to interact with active Gcd/o-GTP (RGS domain), inactive Gcd/o-GDP (GoLoco domain) and with the ras-like GTPases rapl and rap2 (RID domain). Activation of rapl/2 pathways in host cells stimulates MAPK/Erk kinase signaling and neuronal differentiation. Roles for RGS14 as a dual regulator of Gai and Gao signaling are not known. Furthermore, how RGS14, Gcd/o and rapl/2 interact to regulate one anothers functions, and what cellular mechanisms are involved in regulating these interactions and linked cellular responses is not known. Our preliminary studies indicate that RGS14 is phosphorylated by kinases involved in G protein and rap signaling. Our hypothesis is that RGS14 is an integrator of G protein (Ged/o) and rap-directed signaling pathways, and that stimulus-initiated phosphorylation regulates RGS 14 interactions with G_ and rap, its subeellular localization, and its signaling functions. Using modern molecular, cellular and biochemical approaches, the specific aims will be to: 1. Determine roles for RGS I4 as a bifunctional regulator of receptor and God and G(_o signaling in membranes. 2. Define cellular and biochemical mechanisms that regulate RGS 14 membrane recruitment and attachment, subcellular localization, and a-Ssociati0n with mChoR, Gczi/o, and rapl/2 in host B35 cells. 3. Define cellular mechanisms for regulating RGS14 phosphorylation in cells, and roles for phosphorylation on RGS14 interactions with mChoR/Gi/o and rapt/2 in vitro, and linked signaling pathways in B35 cells. 4. Determine the effects of overexpressing RGSI4 or eliminating native RGS14 in B35 cells on mChoR/Gi/o and rapl/2- directed signaling events and cellular responses. Impact: These studies will identify previously unrecognized cell signaling roles for RGS proteins, and provide important information about novel mechanisms for cross-talk between G protein signaling pathways and rap/MAPkinase signaling pathways. Findings from these studies will clarify our understanding of the complexity of G protein/RGS protein signaling, and identify potential new targets for therapeutic intervention. PERFORMANCESITE( ========================================Section End===========================================