G-protein signal coordination by RGS12

描述(由申请人提供)：通过异源三聚体G蛋白偶联受体(GPCRs)及时启动和停止细胞间通讯对于大脑和感觉神经元的正常功能至关重要。这一过程的异常可导致外周或中枢神经系统活动的病理生理缺陷；相反，GPCR信号的刺激、延长或拮抗是许多精神活性和神经药物作用的基础。1996年，一类新的蛋白质被发现，它直接调节GPCR信号传递的时间--“G蛋白信号调节因子”(RGS)蛋白质。西德罗夫斯基实验室的总体目标是确定RGS蛋白在(病理)生理过程中的具体作用，从而确定RGS家族中选定的成员作为可行的药物发现目标。RGS12特异性地参与了GABA(B)受体介导的背根节突触前钙电流抑制的脱敏作用。我们的长期目标是确定构成RGS12脱敏功能的分子决定因素。除了RGS12 RGS结构域所指定的标志性GTP酶加速活性外，我们现在已经确定了RGS12中的磷脂和磷酸酪氨酸结合活性，以及它与丝裂原激活的蛋白激酶(MAPK)级联的多种成分相互作用的能力。因此，该建议描述了对RGS12介导的蛋白质/蛋白质和蛋白质/脂质相互作用的生化/生物物理和细胞生物学分析，以及对激动剂促进的MAPK信号转导的细胞研究，以及在存在选择性RGS12突变体的情况下神经递质对Cav2.2通道活性调节的电生理学评估。这项工作的结果将有助于确定RGS12在信号转导和离子通道调节中的具体作用，并阐明RGS12作为治疗神经病理性疼痛和痉挛的新疗法的药物发现靶点的潜力。许多药物通过结合细胞表面的一种特定的蛋白质受体发挥作用：一种G蛋白偶联受体。我们的团队发现了一个新的蛋白质家族-RGS蛋白质-干扰这些受体。我们希望研究一种RGS蛋白，RGS12，它干扰控制疼痛处理的神经元中神经递质GABA的作用。这项工作应该会导致新的止痛药物的发现。

DESCRIPTION (provided by applicant): Timely initiation and cessation of intercellular communication via heterotrimeric G protein-coupled receptors (GPCRs) is crucial for normal functioning of brain and sensory neurons. Aberration of this process can lead to pathophysiological deficits in peripheral or central nervous system activity; conversely, stimulation, prolongation, or antagonism of GPCR signaling underlies the actions of many psychoactive and neurotropic agents. In 1996, a new class of proteins was discovered that directly modulate the timing of GPCR signaling - the "regulators of G-protein signaling" (RGS) proteins. The overall goal of the Siderovski laboratory is to identify specific roles for RGS proteins in (patho)physiological process and thus establish select members of the RGS family as viable drug discovery targets. RGS12 is specifically involved in determining desensitization from GABA(B) receptor-mediated inhibition of presynaptic calcium current in dorsal root ganglia. Our long-term objective is to define the molecular determinants that constitute the desensitization function of RGS12. Beyond the hallmark GTPase-accelerating activity specified by the RGS12 RGS domain, we have now identified phospholipid- and phosphotyrosine-binding activity within RGS12, as well as its ability to interact with multiple components of the mitogen-activated protein kinase (MAPK) cascade. This proposal therefore describes biochemical/biophysical and cell-biological analyses of RGS12-mediated protein/protein and protein/lipid interactions, coupled with cellular studies of agonist-promoted MAPK signal transduction and electrophysiological assessment of neurotransmitter modulation of Cav2.2 channel activity in the presence of selective RGS12 mutants. Results from this work will help define the specific roles RGS12 partakes in signal transduction and ion channel modulation, as well as illuminate the potential for RGS12 as a drug discovery target for novel therapies for neuropathic pain and spasticity. Many drugs act by binding a particular protein receptor on the cell's surface: a G-protein coupled receptor. Our group discovered a new protein family - the RGS proteins - that interfere with these receptors. We wish to study one RGS protein, RGS12, that interferes with the actions of the neurotransmitter GABA in neurons that control pain processing. This work should lead to the discovery of new pain-controlling drugs.