Functional Architecture of Glutamate Receptor Channels

描述(申请人提供)：我的实验室的长期目标是了解大脑中潜在的信号传递的分子机制，特别是当它与更高的大脑功能和疾病状态有关时。我的实验室主要研究突触生理学，特别是那些使用谷氨酸作为神经递质的突触。谷氨酸受体(GluRs)介导大脑中的基本信息处理，参与学习和记忆的细胞和分子机制，细胞连接的发展和维持，以及疼痛的传导和感知。当功能失调时，GluRs还与许多精神疾病有关，如精神分裂症，以及急性和慢性细胞死亡，包括与各种神经退行性疾病有关的疾病，如阿尔茨海默氏症和帕金森氏病。本方案的目的是定义GluR的结构-功能，主要集中在这些配体门控离子通道的离子通道成分上。这些信息是理解GluRs在大脑功能中的作用以及开发减轻它们在病理条件下介导的细胞死亡的药物的关键。这一问题将在重组GluRs中使用各种技术进行研究，包括定点突变、半胱氨酸扫描、嵌合体、蛋白质化学、可用的晶体结构、快速激动剂的应用以及全细胞、外向外贴片和单通道记录。具体目标#1将研究将配体结合结构域连接到主要跨膜门控结构域M3的连接区的动力学。这一区域代表着调节受体功能的关键节点，因此也是在病理状态下调节受体动态的部位。具体目标#2将研究M4片段对通道功能的功能和结构贡献。所有哺乳动物的GluRs亚基都有一个跨膜片段M4，位于离子通道(M1-M3)核心的C末端。M4是哺乳动物Glur功能所必需的。确定其对这一进程的贡献将澄清GluRs门控的基本机制。具体目标#3将进一步探讨与通道门控相关的问题，特别是脱敏，重点是离子通道和配体结合结构域之间的静电相互作用。这项工作将确定Glur结构-功能的基本原理，并为在精神状态和病理条件下减弱细胞死亡Glur中介的方法提供新的工具和见解。 项目叙述：突触调节大脑中的信息传输，是我们如何思考、行动和学习的中心。许多已被证明在治疗脑部疾病方面取得成功的药物，如阿尔茨海默氏症、帕金森氏病和精神疾病，都作用于突触，因此它们是医学和制药研究的主要焦点。我们的工作研究了一种在哺乳动物大脑中分布最广泛的兴奋性突触中发现的元素-谷氨酸受体，试图确定这种元素如何发挥其功能，以及它在疾病状态下可能如何调节。

DESCRIPTION (provided by applicant): The long-term objective of my laboratory is to understand the molecular mechanisms underlying signaling in the brain, especially as it relates to higher brain function and disease states. My laboratory focuses mainly on synaptic physiology, specifically those synapses that use glutamate as their neurotransmitter. Glutamate receptors (GluRs) mediate basic information processing in the brain and contribute to the cellular and molecular mechanisms underlying learning and memory, the development and maintenance of cellular connections, and pain transduction and perception. When dysfunctional, GluRs have also been implicated in numerous psychiatric disorders such as schizophrenia as well as in acute and chronic cell death including that associated with various neurodegenerative diseases such as Alzheimer's and Parkinson's disease. The goal of the present proposal is to define GluR structure-function, focusing mainly on the ion channel component of these ligand-gated ion channels. Such information is key to understanding the role of GluRs in brain function as well as the development of drugs that attenuate the cell death they mediate under pathological conditions. This issue will be studied in recombinant GluRs using a variety of techniques including site-directed mutagenesis, cysteine scanning, chimeras, protein chemistry, available crystal structures, fast agonist application, and whole-cell, outside-out patches, and single channel recordings. Specific Aim#1 will study the dynamics of the linker regions coupling the ligand-binding domain to M3, the major transmembrane gating domain. This region represents a critical juncture regulating receptor function and hence sites for modulating receptor dynamics under pathological states. Specific Aim#2 will study the functional and structural contribution of the M4 segment to channel function. All mammalian GluRs subunits have a transmembrane segment, M4, located C-terminal to the core of the ion channel (M1-M3). M4 is a necessary requirement for mammalian GluR function. Defining its contribution to this process will clarify fundamental mechanisms of gating in GluRs. Specific Aim#3 will further pursue issues related to channel gating specifically to desensitization, focusing on electrostatic interactions between the ion channel and the ligand-binding domain. This work will define fundamental principles of GluR structure-function and provide new tools and insights into means to attenuate the cell death GluR mediate under psychiatric states and pathological conditions. PROJECT NARRATIVE: Synapses mediate the transfer of information in the brain and are at the center of how we think, act and learn. Many drugs that have proven successful in the treatment of brain diseases such Alzheimer's and Parkinson's Diseases and mental illness act on synapses so they are a major focus of medical and pharmaceutical research. Our work studies one element -glutamate receptors- found at the most wide spread excitatory synapse in the mammalian brain, trying to define how this element carries out its function and how it might be modulated in disease states.