Functional Architecture of Glutamate Receptor Channels

描述（由申请人提供）：我的实验室的长期目标是了解大脑信号传导的分子机制，特别是与高级脑功能和疾病状态相关的分子机制。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，并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也与许多精神疾病（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（如阿尔茨海默病和帕金森病）相关的细胞死亡有关。本提案的目标是定义GluR的结构功能，主要关注这些配体门控离子通道的离子通道成分。这些信息是了解GluRs在脑功能中的作用以及开发药物的关键，这些药物可以减轻它们在病理条件下介导的细胞死亡。这个问题将在重组GluRs中使用各种技术进行研究，包括位点定向诱变、半胱氨酸扫描、嵌合体、蛋白质化学、可用的晶体结构、快速激动剂应用、全细胞、外向外贴片和单通道记录。具体目标#1将研究将配体结合域与M3（主要的跨膜门控域）耦合的连接体区域的动力学。该区域是调节受体功能的关键节点，因此是病理状态下调节受体动态的位点。具体目标#2将研究M4部分对通道功能的功能和结构贡献。所有哺乳动物GluRs亚基都有一个跨膜段M4，位于离子通道核心的c端（M1-M3）。M4是哺乳动物GluR功能的必要条件。确定其对这一过程的贡献将澄清GluRs中门控的基本机制。具体目标#3将进一步探讨与通道门控有关的问题，特别是与脱敏有关的问题，重点关注离子通道和配体结合域之间的静电相互作用。这项工作将明确GluR结构和功能的基本原理，并为减轻GluR介导的精神状态和病理状态下的细胞死亡提供新的工具和见解。

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.