GABA Channel Activation Domains and Mechanisms

GABA 通道激活域和机制

• 批准号: 7890067
• 负责人: DAVID S WEISS
• 金额: $ 46.23万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-08-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7890067
• 关键词: 3-aminobutyric acid; Acetylcholine; Adopted; Agonist; Amino Acids; Aminobutyric Acids; Autistic Disorder; Barbiturates; Benzodiazepines; Binding; Binding Proteins; Binding Sites; Brain; Brain Diseases; Chloride Ion; Chlorides; Cleaved cell; Coupling; Cysteine; DNA Sequence Rearrangement; Data; Disease; Down Syndrome; Electrodes; Environment; Epilepsy; Etiology; Event; Family; Fluorescence; Fluorometry; Functional disorder; GABA Receptor; Gated Ion Channel; Glycine; Hereditary Disease; Hydrophobicity; Investigation; Ion Channel; Ions; Kinetics; Laboratories; Ligand Binding; Ligands; Location; Measurement; Mediating; Mediator of activation protein; Membrane; Modeling; Modification; Molecular; Movement; Nerve; Neurons; Neurotransmitters; Parkinson Disease; Phase; Photoaffinity Labels; Play; Positioning Attribute; Presynaptic Terminals; Process; Receptor Activation; Relative (related person); Research Personnel; Resolution; Role; Site; Site-Directed Mutagenesis; Staging; Structural Models; Structure; Synaptic Transmission; Techniques; Therapeutic; Time; Work; barbituric acid salt; design; fluorophore; gamma-Aminobutyric Acid; insight; interest; luminescence resonance energy transfer; mutant; nervous system disorder; neurosteroids; postsynaptic; presynaptic; prevent; public health relevance; receptor; receptor function; receptor structure function; relating to nervous system; research study; sensor; serotonin receptor; synaptic inhibition; voltage; voltage clamp

DESCRIPTION (provided by applicant): 3-aminobutyric acid, or GABA, is the main inhibitory neurotransmitter in the mammalian brain. Dysfunctions in GABA-mediated inhibition have been implicated in the etiology of a variety of brain disorders. Furthermore, GABA receptors are targets for a host of therapeutic and endogenous modulators such as benzodiazepines, barbiturates, and neurosteroids. Key to understanding the etiology of these diseases and the molecular mechanisms of these modulators, is a detailed understanding of the activation mechanism of the GABA receptor. GABA, released from presynaptic terminals, binds to postsynaptic GABA receptors thereby gating an integral chloride pore. It is this chloride movement across the membrane that reduces the excitability of the postsynaptic neuron. The major focus of my laboratory has been to understand, at the molecular level, the mechanism of this activation process. Our efforts to date have been largely directed at identifying the components of the receptor that are fundamental in this activation process. For example, we have explored the structure of the binding site and identified amino acids that interact with the GABA molecule itself. Other investigations have been directed at locating the gate that keeps the channel closed and exploring the regions that control ion flux through the pore. The next step, and the primary aim of the present application, is to extend this static model of the receptor and begin to define the kinetics of the activation process. Last round, we introduced Voltage-Clamp Fluorometry to the ligand-gated ion channel field. This technique, using an environmentally-sensitive fluorophore attached to defined positions of the receptor, provides an ability to observe structural rearrangements in real time. Simultaneous two-electrode voltage clamp enables a correlation of these rearrangements with channel opening. This round, we will be employing this approach to ask questions about the movements of specific regions of the receptor and to elucidate the role of these movements in the activation process. We ultimately hope to understand the mechanism by which the binding of GABA in the inter-subunit binding cleft leads to the opening of the pore some 50 angstroms away and in the middle of the membrane. In addition to revealing the activation mechanism for these receptors, this information will be crucial for understanding the mechanism of the many GABA receptor modulators and, perhaps, provide information to facilitate the design of new neuroactive compounds that target and modulate GABA receptors in the brain. PUBLIC HEALTH RELEVANCE: GABA receptors are the key mediators of synaptic inhibition in the brain. This project seeks to understand, at the molecular level, how these GABA receptors work. This information is crucial for understanding the dysfunctions in GABA-mediated inhibition that have been implicated in many neural disorders (e.g. epilepsy, Parkinson's Disease, Down's Syndrome, and autism) as well as understanding, and developing new, compounds that target and modulate GABA receptors.

描述（由申请人提供）：3-氨基丁酸或GABA是哺乳动物大脑中的主要抑制性神经递质。 GABA介导的抑制作用的功能障碍与多种脑疾病的病因有关。此外，GABA受体是许多治疗性和内源性调节剂（例如苯二氮卓类药物，巴比妥酸盐和神经素）的靶标。了解这些疾病的病因和这些调节剂的分子机制的关键是对GABA受体的激活机制的详细理解。从突触前末端释放的GABA与突触后的GABA受体结合，从而输入整体氯化孔。正是这种跨膜的氯化物运动降低了突触后神经元的兴奋性。我实验室的主要重点是在分子水平上了解这种激活过程的机制。迄今为止，我们的努力主要致力于确定在这种激活过程中基本的受体组成部分。例如，我们探索了结合位点的结构，并鉴定出与GABA分子本身相互作用的氨基酸。其他调查旨在定位使通道关闭并探索控制离子通量通过孔的区域的门。下一步以及本应用程序的主要目的是扩展受体的静态模型，并开始定义激活过程的动力学。上一轮，我们将电压钳荧光法引入了配体门控离子通道场。该技术使用对受体定义位置的环境敏感的荧光团实时观察结构重排的能力。同时进行两电极电压夹可以使这些重排与通道打开的相关性。这一轮，我们将采用这种方法来询问有关受体特定区域运动的问题，并阐明这些运动在激活过程中的作用。我们最终希望理解GABA在亚基间结合裂缝中的结合导致孔的开口约50埃50埃，而在膜中间的机制。除了揭示这些受体的激活机制外，该信息对于理解许多GABA受体调节剂的机制至关重要，也许提供了信息以促进靶向和调节大脑中GABA受体的新神经活性化合物的设计。 公共卫生相关性：GABA受体是大脑突触抑制的关键介体。该项目试图在分子水平上了解这些GABA受体的工作方式。该信息对于理解GABA介导的抑制功能障碍至关重要，而GABA介导的抑制作用与许多神经疾病（例如癫痫，帕金森氏病，唐氏综合症和自闭症）有关，以及理解以及开发新的，靶向和调节GABA受体的新化合物。