Towards small molecule modulators of RGS proteins

描述（由申请人提供）：神经递质信号传导通常涉及G蛋白偶联受体（GPCR）的激活。调节神经递质受体信号传导是改善诸如精神分裂症和抑郁症等疾病的认知病理的关键治疗工具。“G蛋白信号传导调节因子”（RGS）蛋白是GPCR信号传导的关键组分，其充当Ga亚基的GTP酶加速蛋白或“GAP”，显著增加其内在GTP水解活性。为了推进RGS蛋白作为认知病理学的药物发现靶点的效用，本研究提案的具体目的是通过计算方法描绘RGS-box GAP活性的变构调节的结构决定因素并鉴定RGS-box GAP活性的小分子抑制剂和激活剂。RGS-box序列的统计偶联分析和应用于已知RGS-box结构的位点识别算法将指导来自商业和公共化合物库的化合物的计算机对接。在这些筛选中鉴定的化合物“命中物”的活性将使用基于荧光和表面等离子体共振的RGS-box Ga-结合和Ga-GAP活性的体外测定来评估。然后，将在受体/G蛋白/效应子功能的细胞测定中评价经验证的RGS-box GAP活性调节剂，包括异源三聚体稳态GT α活性和磷脂酶C活性的受体依赖性活化。这些追求应确定RGS蛋白作用的原理性小分子调节剂，其将确立RGS蛋白作为CNS疾病的未来药物治疗中的治疗干预的有效靶标。

DESCRIPTION (provided by applicant): Neurotransmitter signaling often involves activation of G protein-coupled receptors (GPCRs). Modulation of neurotransmitter receptor signaling is a key therapeutic tool in ameliorating the cognitive pathologies of diseases such as schizophrenia and depression. "Regulator of G-protein signaling" (RGS) proteins are key components of GPCR signaling that act as GTPase-accelerating proteins or "GAPs" for Ga subunits, dramatically increasing their intrinsic GTP hydrolysis activity. In order to advance the utility of RGS proteins as drug discovery targets for cognitive pathologies, the specific aims of this research proposal are to delineate the structural determinants of allosteric modulation of RGS-box GAP activity and to identify small molecule inhibitors and activators of RGS-box GAP activity by computational approaches. Statistical coupling analyses of RGS-box sequences and site identification algorithms applied to known RGS-box structures will guide in silico docking of compounds from commercial and public compound libraries. The activity of compound "hits" identified in these screens will be evaluated using fluorescence- and surface plasmon resonance-based in vitro assays of RGS-box Ga-binding and Ga-GAP activities. Verified modulators of RGS-box GAP activity will then be evaluated in cellular assays of receptor/G-protein/effector function, including receptor-dependent activation of heterotrimer steady-state GTPase activity and of phospholipase C activity. These pursuits should identify proof-of-principle small molecule modulators of RGS protein action that will establish RGS proteins as valid targets for therapeutic intervention in future pharmacotherapy of CNS disorders.