Dynamics Of Ligand Gated Ion Channels

项目摘要/摘要 谷氨酸受体介导兴奋在哺乳动物中枢神经系统中的传播，并且 最终控制运动和认知等生理功能。它们被分成四类 亚家族：N-甲基-D-天冬氨酸，-氨基-5-甲基-3-羟基-4-异恶唑丙酸酯， 红藻氨酸和德尔塔受体。所有四个亚型在拓扑结构上都是相似的，由四个蛋白质亚基组成 一起作为二聚体的二聚体。然而，它们的门控特征和机制是独特的，反映了 在突触传递中扮演不同的角色。我的实验室的目标是了解其背后的机制 这些子类型中的每一个的功能微调。使用一种多管齐下的方法，结合生化， 电生理、荧光和计算方法，我们已经确定了构象 对调节AMPA和NMDA谷氨酸受体的激活和抑制至关重要的转变。 然而，直接了解这种结构变化在蛋白质控制的一个部分是如何变化的 其他部分，以及它们如何决定功能属性，仍然是未知的。我们建议开发和使用 多色单分子荧光共振能量转移(FRET)绘制结构-功能图 谷氨酸受体各亚型不同片段间的相关性。我们还将把我们的努力集中在 了解较少研究的红藻酸盐亚型和三角洲亚型。具体地说，我们将调查这些机制 激动剂、离子和辅助剂对丰富形式的红藻氨酸受体的潜在激活和调节 蛋白质。此外，我们有初步数据表明，Delta受体的功能依赖于连接 与跨突触蛋白复合体，因此我们将研究三角洲受体的结构和功能。 突触结合伙伴的上下文。总而言之，这些研究将把我们基本的单分子 生理背景下的研究，并最终使我们能够理解 突触和非突触谷氨酸受体。

PROJECT SUMMARY/ABSTRACT Glutamate receptors mediate the spread of excitation in the mammalian central nervous system, and ultimately control physiological functions such as movement and cognition. They are classified into four subfamilies: N-methyl-D-aspartate (NMDA), -amino-5-methyl-3-hydroxy-4-isoxazole propionate (AMPA), kainate, and delta receptors. All four subtypes are topologically similar, comprising four protein subunits held together as a dimer-of-dimers. However, their gating characteristics and mechanisms are unique, reflecting distinct roles in synaptic transmission. The goal of my laboratory is to understand the mechanisms that underlie the functional fine-tuning of each of these subtypes. Using a multipronged approach that combines biochemical, electrophysiological, fluorescence, and computational methods, we have already identified conformational transitions that are critical for mediating activation and inhibition of AMPA and NMDA glutamate receptors. However, a direct understanding of how such structural changes in one part of the protein control changes in other parts, and how they dictate functional properties, remains unknown. We propose to develop and use multicolor single-molecule fluorescence resonance energy transfer (FRET) to draw structure–function correlations between different segments of each glutamate receptor subtype. We will also focus our efforts on understanding the less well-studied kainate and delta subtypes. Specifically, we will investigate the mechanisms underlying activation and modulation of an abundant form of the kainate receptor by agonists, ions, and auxiliary proteins. In addition, we have preliminary data showing that delta receptor function is dependent on connections with trans-synaptic protein complexes, therefore we will study the structure and function of delta receptors in the context of synaptic binding partners. Together, these investigations will place our fundamental single-molecule investigations in a physiological context, and eventually allow us to understand functional differences between synaptic and non-synaptic glutamate receptors.