Gating and permeation in ionotropic glutamate receptors

 描述(申请人提供)：我工作的总体目标是通过研究NMDA和AMPA受体的运作来确定神经系统中突触传递的分子特征。这些受体是神经递质门控离子通道，将突触前谷氨酸的释放转化为突触后信号。谷氨酸是大脑中主要的兴奋性神经递质。通过定义NMDA和AMPA受体的运作，我们将更好地了解它们是如何控制大脑功能的。我们还将学习如何以更高的精度和特异性调节它们的功能，以帮助理解并有可能治疗精神分裂症、癫痫等疾病状态，以及与急性和慢性大脑疾病相关的兴奋毒性。我们的实验将集中在NMDA和AMPA受体的结构元件上，这些结构元件位于离子通道渗透途径的外围。最近的证据表明，这些外部或外周结构中的遗传和从头突变会导致发育障碍和癫痫脑病。这些外部结构还含有滥用药物的变构部位，是新开发的NMDA受体调节剂的靶标。目标1将解决外部结构对快速和有效的毛孔开放的影响，毛孔开放是快速突触传输的标志。对于这些实验，我们将结合单通道记录和非平衡条件来定义外部结构的位移能量。目标2将阐述离子如何通过外部结构进入中央渗透途径。目标3将解决致病突变如何在外部结构相互作用来改变NMDA和AMPA受体功能。在这里，我们将使用半胱氨酸交联、快速激动剂应用和无激动剂的单通道录音来解决特定元件如何在外部结构中相互作用来调节受体功能。总体而言，我们的实验将描绘外部结构如何对NMDA和AMPA受体的运作做出贡献。这些信息将有助于确定致病突变如何影响受体功能，并有助于开发针对神经系统疾病中这些受体的特定治疗方法。

 DESCRIPTION (provided by applicant): The overall goal of my efforts is to define molecular features of synaptic transmission in the nervous system by studying the operation of NMDA and AMPA receptors. These receptors are neurotransmitter-gated ion channels that convert the presynaptic release of glutamate, the predominant excitatory neurotransmitter in the brain, into a postsynaptic signal. By defining the operation of NMDA and AMPA receptors, we will gain a better understanding of how they control brain function. We will also learn how to modulate their function with greater precision and specificity to help understand, and potentially treat, disease states such as schizophrenia, epilepsy, and the excitotoxicity associated with acute and chronic brain disorders. Our experiments will focus on structural elements of the NMDA and AMPA receptor located to the periphery of those lining the permeation pathway of the ion channel. Recent evidence has indicated that inherited and de novo mutations in these outer or peripheral structures induce developmental disorders and epileptic encephalopathies. These outer structures also contain allosteric sites for drugs of abuse and are targets for newly developed NMDA receptor modulators. Aim 1 will address the impact of the outer structures to the rapid and efficient pore opening that is the hallmark of fast synaptic transmission. For these experiments, we will combine single channel recordings with non-equilibrium conditions to define the energetics of displacement of the outer structures. Aim 2 will address how permeant ions access the central permeation pathway through the outer structures. Aim 3 will address how disease- causing mutations interact at the outer structures to alter NMDA and AMPA receptor function. Here, we will use cysteine cross-linking, fast agonist application, and agonist-free single channel recordings to address how specific elements interact in the outer structures to modulate receptor function. Overall our experiments will delineate how the outer structures contribute to the operation of NMDA and AMPA receptors. This information will aid in defining how disease-causing mutations affect receptor function and in developing specific therapies to target these receptors in nervous system disorders.