Structure and Function of NMDA Receptors

 描述(申请人提供)：N-甲基D-天冬氨酸受体是谷氨酸受体的一种亚型，在哺乳动物中枢神经系统中介导兴奋性信号传递。它们的主要功能包括将化学信号转换为电信号，即谷氨酸与受体中的胞外区域结合触发 受体中的阳离子通透性跨膜通道。鉴于这些受体在调节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必要性，主要问题是激动剂如何激活蛋白质以及如何调节这一机制。NMDA受体是由氨基末端结构域、激动剂结合域、通道片段和C-末端结构域组成的调节剂。在这里，我们建议研究结构域之间的通信以及它们在决定激活和变构调节中的作用。具体地说，我们将结合发光共振能量转移、smFRET和电生理学，研究GluN1激动剂结合结构域与GluN2亚单位之间的相互作用在控制激动剂结合结构域动力学和激活程度(特定目标1)中的作用。我们还将通过建立从氨基末端区域开始通过激动剂结合域的构象变化来研究变构调节的途径，并研究变构调节过程中细胞外域的动力学变化(特定目标2)。光谱研究将得到电生理测量的补充，电生理测量研究由结构域之间的界面变化引起的功能变化。这些功能和结构的研究将提供一个全面的了解构象途径以及动力学在激活和变构调节NMDA受体功能中的作用。

 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. The NMDA receptors are modulator in structure consisting of an amino terminal domain, agonist binding domain, channel segments and the C-terminal domains. Here we propose to study the communication between the domains and their role in dictating activation and allosteric modulation. Specifically we will investigate the role o the interactions between GluN1 agonist binding domain with the GluN2 subunit in controlling agonist binding domain dynamics and extent of activation (specific aim 1) using a combination of luminescence resonance energy transfer, smFRET, and electrophysiology. We will also investigate the pathway for allosteric modulation by establishing the conformational changes starting at the amino terminal domain through the agonist binding domain and study the changes in dynamics in the extracellular domains during the allosteric modulation (specific aim 2). The spectroscopic investigations will be complemented by electrophysiological measurements investigating the changes in function induced by alterations at the interface between the domains. These functional and structural investigations will provide a comprehensive understanding of the conformational pathway as well as role of dynamics in activation and allosteric modulation in NMDA receptor function.