Mechanism for Regulating Kainate-Type Glutamate Receptor Activity

描述（由申请人提供）：本提案的主要目标是了解调节大脑兴奋性突触传递的机制。神经系统疾病，包括智力低下、自闭症、癫痫和共济失调，都是由大脑中神经回路的破坏引起的。神经回路由神经元组成，神经元通过神经递质在突触上相互交流。大脑中最丰富的兴奋性神经递质是谷氨酸。谷氨酸作用于三种类型的离子型谷氨酸受体，AMPA-， NMDA-和kainate型受体。AMPA受体介导快速突触传递，而NMDA受体调节突触可塑性。然而，盐酸盐受体的生理作用尚不清楚。我们最近发现了一种新的跨膜蛋白NETO2，它与盐酸盐受体相互作用，使用无偏倚的蛋白质组学筛选。在异源细胞和神经元中，NETO2调节盐酸盐受体的通道特性，而盐酸盐受体反过来调节NETO2的转运。然而，有几个悬而未决的问题来揭示蓝酸盐受体在大脑中的作用。1. NETO2/kainate受体复合物是如何组装和运输到细胞表面的？NETO2和盐酸盐受体如何相互调节？3. NETO2/kainate受体复合物如何介导突触传递？在本文中，我们将解决这些问题，以揭示蓝酸盐受体/NETO2复合物在大脑中的功能作用。我们将利用不同的转基因小鼠模型，确定海碱盐受体/NETO2复合物的蛋白组装顺序和表面转运机制。我们还将以非洲爪蟾卵母细胞为模型系统，研究NETO2和盐酸盐受体的结构和功能分析。此外，我们将通过电生理实验重构海碱盐受体介导的神经元突触传递，揭示海碱盐受体在兴奋性突触传递中的作用。这些研究将为兴奋性突触的突触传递调节机制和大脑中神经回路的作用提供基本的见解。由于盐酸盐受体在包括自闭症、精神分裂症、癫痫和感觉转导改变在内的几种神经系统疾病中的潜在作用已经被提出，这项工作将为药物发现确定新的靶点。公共卫生相关性：神经系统疾病，包括智力迟钝、自闭症、癫痫和共济失调，都是由大脑神经回路的中断引起的。这一建议的总体目标是了解大脑中调节兴奋性突触传递的机制。这些研究将为兴奋性突触的突触传递调节机制和大脑中神经回路的作用提供基本的见解。由于盐酸盐受体在包括自闭症、精神分裂症、癫痫和感觉转导改变在内的几种神经系统疾病中的潜在作用已经被提出，这项工作将为药物发现确定新的靶点。

DESCRIPTION (provided by applicant): The broad goal of this proposal is to understand mechanisms for regulating excitatory synaptic transmission in the brain. Neurological diseases, including mental retardation, autism, epilepsy, and ataxia, are caused by the disruption of neural circuits in the brain. Neural circuits consist of neurons that communicate with each other at synapses through neurotransmitters. The most abundant excitatory neurotransmitter in the brain is glutamate. Glutamate acts on three classes of ionotropic glutamate receptors, AMPA-, NMDA- and kainate-type receptors. AMPA receptors mediate fast synaptic transmission, whereas NMDA receptors modulate synaptic plasticity. However, the physiological roles of kainate receptors remain unclear. We have recently identified a novel transmembrane protein, NETO2 that interacts with the kainate receptor, using an unbiased proteomic screen. In heterologous cells and neurons, NETO2 modulates the channel properties of kainate receptors, and kainate receptors, in turn, modulate NETO2 trafficking. However, there are several unanswered questions to reveal roles of kainate receptors in the brain. 1. How does NETO2/kainate receptor complex assemble and traffic to the cell surface 2. How do NETO2 and kainate receptors modulate each other? 3. How does NETO2/kainate receptor complex mediate the synaptic transmission? In this proposal, we will address these questions to reveal functional roles of kainate receptor/NETO2 complex in the brain. We will identify protein assembling order of kainate receptor/NETO2 complex and mechanisms for surface trafficking using various transgenic mouse model. We will also examine structure and functional analysis of NETO2 and kainate receptors using Xenopus laevis oocyte as a model system. Furthermore, we will reconstitute kainate receptor mediated synaptic transmission in neurons to reveal roles of kainate receptors in excitatory synaptic transmission with electrophysiological experiments. These studies will provide fundamental insights into the mechanisms that regulate synaptic transmission at excitatory synapses regards to roles of neural circuits in the brain. Because potential roles of kainate receptors in several neurological diseases including autism, schizophrenia, epilepsy and altered sensory transduction have been proposed, this work will identify novel targets for drug discovery. PUBLIC HEALTH RELEVANCE: Neurological diseases, including mental retardation, autism, epilepsy, and ataxia, are caused by the disruption of neural circuits in the brain. The broad goal of this proposal is to understand mechanisms for regulating excitatory synaptic transmission in the brain. These studies will provide fundamental insights into the mechanisms that regulate synaptic transmission at excitatory synapses regards to roles of neural circuits in the brain. Because potential roles of kainate receptors in several neurological diseases including autism, schizophrenia, epilepsy and altered sensory transduction have been proposed, this work will identify novel targets for drug discovery.