RGS6 Signaling and Function in Neural Development

描述（由申请人提供）：G蛋白信号（RGS蛋白）的调节因子是某些Galpha亚基的gtpase激活蛋白（gap），因此具有调节Galpha和Gbetagamma亚基在体内的活性寿命的潜力。目前关于RGS蛋白的知识的一个主要限制是了解它们在体内的生理作用和结构差异在它们的信号功能中的作用。在这里，我们提供了人类RGS6蛋白家族异常复杂性的新证据，并鉴定了这些蛋白的新蛋白相互作用和信号功能。我们鉴定了20种RGS6的剪接变体形式，它们都具有针对Galpha亚基的GAP活性所需的结构域。我们发现RGS6蛋白与神经元特异性微管不稳定蛋白scg10的相互作用可促进PC12细胞的神经元分化。我们还发现，斑马鱼胚胎中RGS6蛋白的过表达，在那里我们发现了RGS6转录物的神经表达，产生了显著的神经发育效应。该提案旨在为我们对RGS6蛋白的理解提供新的结构和功能见解。RGS6蛋白的结构差异及其与SCG10和Gbeta5（与RGS6蛋白的GGL （γ -亚基样）结构域结合的蛋白）的相互作用在其调节G蛋白信号传导和神经元分化能力中的作用尚不清楚。我们将描述RGS6蛋白及其结合伙伴在细胞系统中G蛋白信号传导中的作用及其相互作用。我们将定义RGS6的GGL结构域内结合G？和SCG10，并检查这种效应的特异性和普遍性。我们将确定RGS6蛋白诱导神经突生长和微管破坏的机制。我们将通过野生型和突变型RGS6蛋白的功能获得和基因敲低方法，在实验可调节的斑马鱼中表征RGS6在神经发育中的作用及其与结合伙伴的相互作用。这项工作将为RGS蛋白新信号传导作用的分子基础提供新的结构和功能见解，并将为理解RGS6在神经发育中的功能机制做出重要贡献。

DESCRIPTION (provided by applicant): Regulators of G protein signaling (RGS proteins) are GTPase-activating proteins (GAPs) for certain Galpha subunits and, therefore, possess the potential to regulate the active lifetimes of both Galpha and Gbetagamma subunits in vivo. A major limitation of current knowledge concerning RGS proteins is understanding their physiological roles in vivo and the role of structural differences in their signaling functions. Here we provide new evidence of extraordinary complexity in the human RGS6 protein family and the identification of novel protein interactions and signaling functions of these proteins. We identified 20 splice variant forms of RGS6, all of which possess the domain required for GAP activity toward Galpha subunits. We discovered that RGS6 protein interaction with SCG 10, a neuron-specific microtubule-destabilizing protein, promotes neuronal differentiation of PC12 cells. We also found that overexpression of RGS6 proteins in zebrafish embryos, where we identified neural expression of RGS6 transcripts, produced marked neural development effects. This proposal is designed to provide new structural and functional insights into our understanding of RGS6 proteins. The role of structural differences in RGS6 proteins and their interactions with SCG10 and Gbeta5, proteins that bind to the GGL (Ggamma-subunit like) domain of RGS6 proteins, in their ability to regulate G protein signaling and neuronal differentiation is unknown. We will characterize the role of RGS6 proteins and interactions with their binding partners on G protein signaling in cellular systems. We will define the residues or motifs within the GGL domain of RGS6 that bind G? and SCG10 and examine the specificity and generality of this effect. We will determine the mechanisms underlying the ability of RGS6 proteins to induce neurite outgrowth and microtubule disruption. We will characterize the role of RGS6 in neural development and its interaction(s) with its binding partners by gain of function and gene knockdown approaches with wild type and mutant RGS6 protein in the experimentally amenable zebrafish. This work will provide new structural and functional insights into the molecular basis of novel signaling actions of RGS proteins and will contribute in significant ways to understanding these mechanisms of RGS6 function in neural development.