Molecular Mechanisms of UBE3A Mediated Synapse Development in Angelman Syndrome

描述(由申请人提供)：这项新的申请专注于确定UBE3A缺失导致突触功能障碍的机制。基于广泛的先前发现，我们的总体假设是UBE3A调节对神经发育至关重要的底物蛋白的水平，并且UBE3A活性的中断会导致这些底物水平过高，导致Angelman综合征(AS)中观察到的神经元功能障碍。建议的研究旨在提供对UBE3A信号异常和AS表型之间联系的更好的理解。作为一个长期目标，我们的发现将有助于开发对错误调节的UBE3A底物进行药理学操作的新方法，从而产生治疗AS和其他可能的非综合征性自闭症的新的创新方法。具体地说：目的1.确定Ephexin5水平升高对AS相关表型的贡献，检验Ube3a突变小鼠Ephexin5表达升高导致AS相关突触和行为表型的假说；目的2.确定控制UBE3A介导Ephexin5泛素化的分子机制，检验Ephexin5上不同的蛋白质序列和其他辅助因子在空间和时间上控制UBE3A介导的Ephexin5泛素化的假说；目的3.鉴定UBE3A的神经底物，检验额外的UBE3A底物参与AS病因的假说。

DESCRIPTION (provided by applicant): This new application focuses on the determination of the mechanism by which loss of UBE3A leads to synaptic dysfunction. Based on extensive prior findings, our overall hypothesis is that UBE3A operates to regulate levels of substrate proteins important for neural development, and that disruption of UBE3A activity leads to inappropriately high levels of these substrates, causing the neuronal dysfunctions observed in Angelman Syndrome (AS). The proposed studies are designed to provide improved understanding of the link between aberrations of UBE3A signaling and AS phenotypes. As a long-term goal, our findings will aid in the development of novel approaches for pharmacological manipulation of mis-regulated UBE3A substrates, resulting in new and innovative approaches for the treatment of AS, and possibly other non-syndromic autistic disorders. Specifically: Aim 1. To determine the contribution of elevated Ephexin5 levels to AS- associated phenotypes, to test the hypothesis that elevated Ephexin5 expression in Ube3a mutant mice result in AS-associated synaptic and behavioral phenotypes; Aim 2. To determine the molecular mechanisms controlling UBE3A-mediated Ephexin5 ubiquitination, to test the hypothesis that distinct protein sequences on Ephexin5 and additional cofactors spatially and temporally control UBE3A mediated ubiquitination of Ephexin5; Aim 3. To identify neural substrates of UBE3A, to test the hypothesis that additional UBE3A substrates participate in the etiology of AS.