Modulation of GABAB receptor signaling

GABAB 受体信号传导的调节

• 批准号: 7428849
• 负责人: Stephen J Moss
• 金额: $ 36.06万
• 依托单位: TUFTS UNIVERSITY BOSTON
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-06-01 至 2009-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7428849
• 关键词: 14-3-3 Proteins; Address; Adenylate Cyclase; Agonist; Anoxia; Aspartate; Baclofen; Binding; Biochemical; Biological; Brain; Cell Surface Receptors; Cell surface; Cells; Condition; Coupling; Cytoplasmic Tail; Development; Dimerization; Disease; Electrostatics; Epilepsy; Exhibits; Figs - dietary; G-Protein-Coupled Receptors; GABA Receptor; Golgi Apparatus; Half-Life; In Vitro; Mediating; Membrane Protein Traffic; Mental Depression; Mental Retardation; Molecular; Neurons; Nociception; Numbers; Pathway interactions; Phosphorylation; Phosphorylation Site; Phosphotransferases; Play; Population; Process; Production; Protein Kinase; Proteins; Rate; Receptor Signaling; Recombinants; Regulation; Role; Serine; Site; Tail; Testing; addiction; desensitization; inward rectifier potassium channel; mutant; neuroprotection; novel therapeutics; painful neuropathy; protein transport; receptor; receptor function; response; synaptic inhibition; therapeutic target; trafficking; voltage

DESCRIPTION (provided by applicant): GABAB receptors are the major sites of slow synaptic inhibition in the brain. Changes in GABAB receptor function play key roles in epilepsy, nociception, depression, addiction, mental retardation and neuroprotection. The number of GABAB receptors expressed on the cell surface of neurons is dependent on the formation of heterodimers between GABABR1 and R2 subunits. Recent studies have demonstrated that once at the cell surface GABAB receptors are stable entities, which do not undergo agonist-induced internalization. Therefore primary determinants of the efficacy of slow synaptic inhibition mediated by GABAB receptors will be the production of receptor heterodimers, the trafficking of assembled heterodimers to the cell surface, and their coupling to the appropriate effectors. Here we hypothesize that GABAB receptor activity is regulated by the activity of AMP-dependent protein kinase (AMPK), which phosphorylates serine residues within both receptor subunits. Phosphorylation increases GABAB receptor cell surface expression levels by enhancing receptor trafficking and assembly in the secretory pathway. In addition, phosphorylation by AMPK enhances receptor-effector coupling by reducing desensitization. Therefore AMPK activity provides a dynamic mechanism for regulating the efficacy of GABAB receptor signaling. We will use a combination of cell biological, biochemical and electrophysiological approaches to carry out three independent but related specific aims: 1. To test the hypothesis that GABAB receptor are dynamically phosphorylated by intimately associated AMPK. 2. To test the hypothesis that direct phosphorylation of GABAB receptor by AMPK regulates receptor cell surface stability and effector coupling. 3. To test the hypothesis that AMPK activity modifies GABAB receptor membrane trafficking and assembly. Together, our approaches will provide a more thorough understanding of the cell surface stability and function of GABAB receptors. The results of these studies will have the potential to make significant contributions to the development of novel therapeutic strategies for such debilitating disorders as epilepsy, nociception, depression, addiction, and mental retardation.

描述（申请人提供）：GABAB受体是大脑中缓慢突触抑制的主要位点。GABAB受体功能的改变在癫痫、伤害性、抑郁、成瘾、智力迟钝和神经保护中起关键作用。GABAB受体在神经元细胞表面表达的数量取决于GABABR1和R2亚基之间异源二聚体的形成。最近的研究表明，一旦在细胞表面，GABAB受体是稳定的实体，不经历激动剂诱导的内化。因此，GABAB受体介导的慢突触抑制效果的主要决定因素将是受体异二聚体的产生，组装的异二聚体到细胞表面的运输，以及它们与适当的效应器的偶联。在这里，我们假设GABAB受体的活性是由amp依赖性蛋白激酶（AMPK）的活性调节的，AMPK使两个受体亚基内的丝氨酸残基磷酸化。磷酸化通过增强分泌途径中的受体运输和组装来增加GABAB受体细胞表面表达水平。此外，AMPK的磷酸化通过降低脱敏来增强受体-效应物偶联。因此，AMPK活性为调节GABAB受体信号传导的有效性提供了一个动态机制。我们将结合细胞生物学、生物化学和电生理学的方法来实现三个独立但相关的具体目标：