Structure and Function of NMDA Receptors

NMDA 受体的结构和功能

• 批准号: 8474787
• 负责人: Vasanthi Jayaraman
• 金额: $ 28.48万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-30 至 2015-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8474787
• 关键词: AMPA Receptors; Address; Affinity; Agonist; Binding; Biochemical; Cations; Cells; Chemicals; Cleaved cell; Clinical Treatment; Complement; Disease; Dissociation; Extracellular Domain; Fluorescence Resonance Energy Transfer; Gated Ion Channel; Glutamate Receptor; Glutamates; Glycine; Human; Investigation; Ion Channel Protein; Ligands; Measurement; Measures; Mediating; Methods; Molecular; Molecular Conformation; Motor; N-Methyl-D-Aspartate Receptors; N-terminal; Nature; Neuraxis; Physiological Processes; Play; Process; Proteins; Roentgen Rays; Role; Series; Signal Transduction; Structure; Testing; base; cognitive control; dimer; extracellular; ifenprodil; inhibitor/antagonist; insight; luminescence resonance energy transfer; mutant; receptor; receptor function; response; single molecule; single-molecule FRET; small molecule; transmission process

DESCRIPTION (provided by applicant): N-methyl D-aspartate receptors, are a subtype of glutamate receptors that mediate excitatory signal transmission in the mammalian central nervous system. Their primary function involves converting the chemical signal into an electrical signal, i.e. glutamate binding to an extracellular domain in the receptor triggers the formation of cation permeable transmembrane channels in the receptor. Given the importance of these receptors in mediating a number of physiological processes and the need to modulate their function in disease states, the primary questions are how does the agonist activate the protein and how can this mechanism be modulated. To address this question, we propose to use a combination of spectroscopic and biochemical methods to identify the complete conformational landscape of the agonist binding domain and the N-terminal modulator binding domain, in the presence of agonists and modulators that induce a large spectrum of activity. Our hypothesis based on the structures of the isolated components and the electrophysiological measurements of the NMDA receptor and the closely related AMPA receptors is that the activity of the receptor is controlled by the fraction of the agonist binding domain and the N-terminal domain that are in a closed cleft conformation in the receptor. We propose to test this hypothesis by using single molecule and ensemble FRET investigations to probe the conformational changes, which will then be correlated to functional consequences as determined by single channel and whole cell current recordings. Additionally, we hypothesize that the negative cooperativity between the agonist glycine and glutamate is mediated by the interface contacts within and across the dimers, in the dimer of dimer structure of the receptor. To test this hypothesis we will investigate the effect of stabilizing and destabilizing the dimer interface as well as the inter dimer interface in the agonist binding domain on the function as measured by the rates of agonist dissociation. The function based studies will be further corroborated structurally by measuring distance changes across the subunit using LRET. These functional and structural investigations will provide a comprehensive understanding of the mechanism by which agonists and modulators mediate NMDA receptor function.

描述（由申请人提供）：N-甲基D-天冬氨酸受体是谷氨酸受体的亚型，介导哺乳动物中枢神经系统中的兴奋性信号传递。它们的主要功能涉及将化学信号转化为电信号，即谷氨酸与受体中的细胞外结构域的结合触发受体中阳离子可渗透的跨膜通道的形成。鉴于这些受体在介导许多生理过程中的重要性以及在疾病状态下调节其功能的需要，首要问题是激动剂如何激活蛋白质以及如何调节这种机制。为了解决这个问题，我们建议在存在诱导大范围活性的激动剂和调节剂的情况下，结合使用光谱和生化方法来鉴定激动剂结合结构域和N末端调节剂结合结构域的完整构象景观。我们基于分离成分的结构以及 NMDA 受体和密切相关的 AMPA 受体的电生理学测量的假设是，受体的活性是由激动剂结合结构域和 N 端结构域的部分控制的。受体中的闭合裂隙构象。我们建议通过使用单分子和整体 FRET 研究来探测构象变化来测试这一假设，然后将其与单通道和全细胞电流记录确定的功能后果相关联。此外，我们假设激动剂甘氨酸和谷氨酸之间的负协同作用是由受体二聚体结构的二聚体中二聚体内部和之间的界面接触介导的。为了检验这一假设，我们将研究稳定和不稳定二聚体界面以及激动剂结合域中二聚体间界面对通过激动剂解离速率测量的功能的影响。基于功能的研究将通过使用 LRET 测量跨亚基的距离变化在结构上得到进一步证实。这些功能和结构研究将提供对激动剂和调节剂介导 NMDA 受体功能的机制的全面了解。