The role of ubiquitination in regulating GABA(A) receptor functional expression

描述（由申请人提供）：氨基丁酸（GABAA）受体是脑中突触抑制的关键部位，并且是包括苯二氮卓类、巴比妥类、全身麻醉剂和神经类固醇的治疗剂的关键药物靶标。此外，受损的GABAa受体功能是许多CMS病理学的核心，包括癫痫、焦虑、睡眠障碍、成瘾、自闭症、精神发育迟滞、抑郁症和精神分裂症。赖氨酸残基的泛素化是调节蛋白质半衰期和内吞命运的常用细胞机制。这种公认的范式与我们的初步研究一起，使我们制定了一个中心假设，推动本提案中描述的实验：GABAA受体受到直接泛素化的赖氨酸残基与细胞内结构域的个别受体亚基，一个过程，是受神经元活动的动态调制。取决于泛素化的亚基，这种共价修饰起到减少分泌途径内的受体半衰期或增强溶酶体靶向的作用，从而调节GABAA受体细胞表面稳定性和突触抑制的功效。我们的努力将集中在四个互补但不同的实验目标：1。为了验证GABAA受体3亚基泛素化通过调节质膜上的插入来调节受体细胞表面稳定性的假设2。为了验证GABAA受体？2亚基泛素化通过调节溶酶体靶向调节受体细胞表面稳定性3。为了验证泛素化调节GABAA受体4介导的突触抑制的功效的假设。为了检验神经元活动通过调节受体泛素化来调节GABAA受体细胞表面稳定性的假设，我们的方法将提供对调节GABAA受体在突触位点积累的主要决定因素的更透彻的理解。这些研究的结果将有可能为癫痫、焦虑、睡眠障碍、成瘾、自闭症、精神发育迟缓、抑郁症和精神分裂症等衰弱性疾病的新型治疗策略的开发做出重大贡献。

DESCRIPTION (provided by applicant): ?-aminobutyric acid (GABAA) receptors are key sites of synaptic inhibition in the brain and are critical drug targets for therapeutic agents including benzodiazepines, barbiturates, general anesthetics and neurosteroids. Moreover compromised GABAA receptor function is central to a number of CMS pathologies including epilepsy, anxiety, sleep disorders, addiction, autism, mental retardation, depression and schizophrenia. Ubiquitination of lysine residues is a commonly used cellular mechanism to regulate both protein half-life and the endocytic fate. This accepted paradigm together with our preliminary studies has led us to formulate a central hypothesis driving the experiments described in this proposal: GABAA receptors are subject to direct ubiquitination of lysine residues with the intracellular domains of individual receptor subunits, a process that is subject to dynamic modulation by neuronal activity. Depending on the subunit ubiquitinated this covalent modification acts to decrease receptor half-life within the secretory pathway or enhances lysozomal targeting, thereby modulating GABAA receptor cell surface stability and the efficacy of synaptic inhibition. Our efforts will center on four complementary but distinct experimental goals: 1. To test the hypothesis that GABAA receptor ¿3 subunit ubiquitination regulates receptor cell surface stability by modulating insertion at the plasma membrane 2. To test the hypothesis that GABAA receptor ?2 subunit ubiquitination regulates receptor cell surface stability by modulating lysozomal targeting 3. To test the hypothesis that ubiquitination modulates the efficacy of synaptic inhibition mediated by GABAA receptors 4. To test the hypothesis that neuronal activity regulates GABAA receptor cell surface stability by modulating receptor ubiquitination Together, our approaches will provide a more thorough understanding of the primary determinants that regulate accumulation of GABAA receptors at synaptic sites. 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, anxiety, sleep disorders, addiction, autism, mental retardation, depression and schizophrenia.