Activity-dependent regulation of neuronal GIRK channels

描述(申请人提供)：G蛋白偶联内向整流钾通道(GIRK)通过介导脑内各种递质的突触后抑制效应来调节神经元的兴奋性。最近的研究表明，树突棘中存在GIRK，提示兴奋性神经递质受体可能调节GIRK的功能。事实上，神经元活动以蛋白质合成和蛋白磷酸酶(PPI)依赖的方式增加了海马神经元树突和棘中GIRK表面的表达。这项建议的目的是研究活性诱导的GIRK表面表达的分子机制和生理后果。将进行活体成像和表面免疫染色，以研究蛋白质合成、翻译后GIRK的表面转运和PP1活性如何促进活性诱导的GIRK表面表达(特定目标A-C)。为了研究活动诱导的GIRK表面表达的功能意义(特异性靶点D)，我们将对神经元活动前后GABAB介导的GIRK电流进行全细胞膜片钳记录。这些研究将揭示调节抑制性突触功能的新机制

DESCRIPTION (provided by applicant): G-protein coupled inwardly rectifying potassium channel (GIRK) regulates neuronal excitability by mediating postsynaptic inhibitory effects of various transmitter in brain. Recent studies showing the presence of GIRK in dendritic spines suggest that excitatory neurotransmitter receptors may regulate GIRK function. Indeed, neuronal activity increased GIRK surface expression in dendrites and spines of hippocampal neurons in a protein synthesis and a protein phosphatase (PPI)-dependent manner. The objectives of this proposal are to investigate the molecular mechanisms and physiological consequence of activity-induced GIRK surface expression. Live-imaging and surface immunostaining will be performed to investigate how protein synthesis, post translational surface trafficking of GIRK and PP1 activity contribute to activity-induced GIRK surface expression (Specific Aim A-C). To study the functional significance of activity-induced GIRK surface expression (Specific Aim D), whole-cell patch clamp recording of GABAb-mediated GIRK current before and after neuronal activity will be performed. These studies will reveal novel mechanisms for modulating inhibitory synaptic function