Regulation of Striatal GPCR Signaling

纹状体中的G蛋白偶联受体(GPCR)信号转导通路，一个主要的奖励- 大脑中的加工核，在药物成瘾的发展过程中起着举足轻重的作用。许多药物滥用 包括阿片类药物和精神刺激剂通过激活纹状体表达的GPCRs而产生作用 神经元。我们的长期目标是阐明调节细胞外信号转导的分子和细胞机制 纹状体GPCRs是理解导致物质依赖和 设计治疗矫正的策略。 越来越多的证据表明，G蛋白信号转导(RGS)蛋白的调节器在 控制gpr通路与成瘾有关。RGS蛋白用于抑制G蛋白信号转导，因此 处于最佳地位，可以自然地抵消滥用药物过度激活GPCRs的作用。小的 以RGS蛋白为靶点的分子疗法正在成为一种很有前途的治疗策略。然而， RGS在调节纹状体G蛋白通路中的作用机制尚不清楚。这项建议 重点描述了纹状体RGS关键的分子、细胞和行为机制 蛋白质：R7-RGS复合体调节纹状体神经元的信号传递。在之前的一段时间里，我们做出了 在理解R7-RGS方面取得了实质性进展，包括解决其高分辨率结构，定义其G 蛋白质选择性和cAMP的鉴定是参与其作用的关键第二信使系统。 这些观察依赖于我们开发的一系列创新工具和方法来研究纹状体GPCR 具有高精度的信号。 根据积累的数据，我们假设阿片和多巴胺受体信号的控制通过G 蛋白Gao通过变构调控下游的cAMP产生效应物，腺苷环化酶 亚基R7-RGS复合体对成瘾药物的行为行为起着至关重要的作用。这一假设将是 通过追求三个相辅相成的特定目标进行测试，寻求(1)描绘RGS-GaO的功能角色 控制cAMP动力学的轴，(2)决定RGS复合体组织的结构/功能力学 以及(3)探讨RGS-GAO在控制阿片类药物反应中的行为和回路相关性。 精神刺激剂。为解决这些目标而提出的战略将需要基因、 生化和生理学方法，利用一系列强大的试剂，动物 模型，以及允许检查体内信号变化的创新分析。

G protein Coupled Receptor (GPCR) signal transduction pathways in the striatum, a major reward- processing nucleus in the brain, play a pivotal role in the development of drug addiction. Many drugs of abuse including opioids and psychostimulants produce their effects by activating GPCRs expressed by striatal neurons. Our long-term goal is to elucidate molecular and cellular mechanisms that regulate signaling of the striatal GPCRs as a necessary prerequisite to understanding events that lead to substance dependence and designing strategies for the therapeutic correction. Increasing evidence suggests that Regulators of G Protein Signaling (RGS) proteins play a crucial role in controlling GPCR pathways implicated in addiction. RGS proteins serve to curb G protein signaling and thus are optimally positioned to naturally counteract excessive activation of GPCRs by drugs of abuse. Small molecule therapeutics targeting RGS proteins are emerging as promising therapeutic strategies. However, the mechanisms of RGS action in regulation of striatal G protein pathways are poorly understood. This proposal is focused on delineating the molecular, cellular and behavioral mechanisms by which key striatal RGS protein: the R7-RGS complex regulates signaling in striatal neurons. During the previous period, we made substantial progress in understanding R7-RGS including solving its high-resolution structure, defining its G protein selectivity and identification of cAMP to be critical second messenger system involved in its effects. These observations relied on a host of innovative tools and approaches we developed to study striatal GPCR signaling with high degree of precision. Based on accumulated data we hypothesize that control of opioid and dopamine receptor signaling via G Protein Gao to the downstream cAMP producing effector, adenylate cyclase by allosterically regulated multi- subunit R7-RGS complexes critically shapes behavioral actions of addictive drugs. This hypothesis will be tested by pursuing three complementary Specific Aims that seek to (1) delineate functional role of RGS - Gao axis in controlling cAMP dynamics, (2) determine structure/functional mechanics of RGS complex organization and (3) probe behavioral and circuit relevance of RGS-Gao in controlling responses to opioids and psychostimulants. The strategy proposed to address these Aims will entail a synergistic combination of genetic, biochemical, and physiological approaches, exploiting the existence of a powerful array of reagents, animal models, and innovative assays that allow examining signaling changes in vivo.