Regulation of glutamate receptors at synapses by WD40 repeat proteins and the deubiquitinating enzyme USP-46 in C. elegans

这个项目将增加我们对神经元如何在分子水平上相互交流的基本理解。神经元间的交流对于正常的大脑功能以及学习和记忆是必不可少的。神经元通过称为突触的特殊连接点相互交流。神经元释放化学信号，如神经递质谷氨酸，下游神经元通过称为谷氨酸受体（GluRs）的特殊蛋白质探测器接收这些信号。改变突触上的视胶质细胞的数量或水平，可以让神经元改变它们之间的交流，从而使大脑能够学习、适应和储存记忆。该项目的具体重点是研究一个新的蛋白质家族如何通过泛素系统阻止其降解来控制突触中GluRs的数量。泛素是一种可以以高度控制的方式附着和从其他蛋白质上去除的标签。泛素标记的蛋白质被靶向到细胞垃圾中进行降解。本研究研究了三种蛋白如何共同作用，特异性地从GluRs中去除泛素，从而使它们免于降解并增加突触中的受体水平。此外，该项目还为本科生开发和推出了创新的、基于发现的分子遗传学和细胞生物学实验课程，培养研究生和博士后，并为高中教师和少数民族本科生提供研究机会。泛素是突触发育和功能的重要调节因子。大约有100种去泛素化酶（DUBs）可以从其他蛋白质中去除泛素，但是对于在突触中起作用的DUBs知之甚少。获奖实验室最近确定USP-46是第一个调节GluRs的DUB。本文研究了WDR-20和WDR-48两种蛋白如何相互作用并调节USP-46的活性来控制突触上的GluRs水平，并测试了这些分子变化如何影响行为。本研究采用遗传学、生化、定量影像学和行为学等方法，对已建立的遗传模式生物秀丽隐杆线虫中的GluRs进行了研究。秀丽隐杆线虫的优势包括强大的遗传工具，简单而明确的神经系统，以及简单的行为分析，将神经元功能与整个动物行为联系起来。涉及突触发育和功能的基本机制从线虫到人类都是保守的。了解突触的分子变化如何影响神经元的交流和行为，将为改善学习和记忆提供基础信息，并开始揭示学习和行为障碍的分子基础。

This project will increase our fundamental understanding of how neurons communicate with each other at the molecular level. Neuronal communication is essential for normal brain function and for learning and memory. Neurons communicate with each other at specialized junctions called synapses. Neurons release chemical signals, such as the neurotransmitter glutamate, which are received by downstream neurons via specialized protein detectors called glutamate receptors (GluRs). Changing the number or levels of GluRs at the synapse allows neurons to alter their communication, which enables the brain to learn, adapt and store memories. The specific focus of this project is to study how a new family of proteins control the number of GluRs at the synapse by preventing their degradation via the ubiquitin system. Ubiquitin is a tag that can be attached and removed from other proteins in a highly controlled manner. Proteins marked with ubiquitin are targeted to the cellular trash for degradation. This proposal studies how three proteins function together to specifically remove ubiquitin from GluRs, thus rescuing them from degradation and increasing receptor levels at the synapse. In addition, this project develops and launches an innovative, discovery-based Molecular Genetics and Cell Biology Lab Course for undergraduates, trains graduate students and postdoctoral fellows, and provides research opportunities for high school teachers and minority undergraduates. Ubiquitin is an important regulator of synapse development and function. There are about 100 deubiquitinating enzymes (DUBs) that remove ubiquitin from other proteins, however very little is known about the DUBs that function at the synapse. The awardee's lab recently identified USP-46 as the first DUB to regulate GluRs. This proposal investigates how two proteins, WDR-20 and WDR-48, interact and regulate the activity of USP-46 to control GluRs levels at the synapse, and tests how these molecular changes affect behavior. This study uses genetic, biochemical, quantitative imaging and behavioral methods to study GluRs in the well-established genetic model organism C. elegans. Advantages of C. elegans include powerful genetic tools, a simple and defined nervous system, and simple behavioral assays to correlate neuronal function with whole animal behavior. The basic mechanisms involved in synapse development and function are conserved from nematodes to humans. Understanding how molecular changes at the synapse impact neuronal communication and behavior will provide fundamental information that could be applied to improve learning and memory, and to begin to uncover the molecular basis of learning and behavioral disorders.