Probing allosteric surfaces of NMDA receptors

描述(由申请人提供)：许多内源性和合成的配体调节NMDA受体的活性，是许多神经疾病治疗干预的潜在候选者。到目前为止，控制NMDA受体介导的整体通量的经验尝试在临床上只取得了一定的成功，这主要是由于对NMDA受体活性的变构控制机制以及这些活动在脑生理和病理中所起的具体作用了解不足。在过去的资助阶段，目标一直是描绘内源性调节剂(质子、锌/异丙苯地尔、甘氨酸)影响NMDA受体门控动力学的机制，从而控制与突触信号相关的宏观反应。在下一个资金阶段，目标是描绘构成NMDA受体激活的细胞内蛋白质运动。一般的方法是利用最近解决的GluA2四聚体受体、NMDA受体同系物的原子分辨结构以及我们在NMDA受体门控调制方面日益增长的专业知识。我们将引入突变来扰动(增加和降低)NMDA受体结构模块的相对迁移率，并将通过单分子信号的动力学分析来描述伴随而来的反应机制的变化。此外，我们将探索从内部运动受限或增强的受体获得宏观反应的时间过程，以更好地了解特定的结构特征如何支持NMDA受体在脑生理和病理中发挥的独特生物功能。总体而言，这项工作将提供关于NMDA受体激活的结构相关的关键信息，并将整合目前孤立的门控结构和动力学模型。鉴于谷氨酸受体介导了大脑90%以上的兴奋性传递，而NMDA受体对许多基本大脑功能至关重要，拟议中的实验所产生的知识可能会对神经传递和神经调节领域产生广泛的影响。 公共卫生相关性：NMDA受体介导基本的大脑过程，是包括中风、慢性神经退行性变、成瘾和疼痛在内的许多神经病理的治疗靶点。这一应用的结果将提供有关NMDA受体激活的结构相关的所需信息，并通过整合门控的结构和动力学模型，将有助于合理设计治疗急性和慢性神经疾病的药理学方法。

DESCRIPTION (provided by applicant): Numerous endogenous and synthetic ligands modulate NMDA receptor activities and are potential candidates for therapeutic intervention in a number of neurologic disorders. To date, empirical attempts to control en masse NMDA receptor-mediated fluxes have had only modest success in the clinic, mainly due to inadequate understanding of the mechanisms governing the allosteric control of NMDA receptor activities and of the specific roles played by these activities in brain physiology and pathology. Over the previous funding period the objective has been to delineate the mechanisms by which endogenous modulators (protons, zinc/ifenprodil, glycine) affect NMDA receptor gating dynamics and thus control the macroscopic response relevant to synaptic signaling. Over the next funding period the objective is to delineate the intracellular protein motions that constitute the NMDA receptor activation. The general approach is to capitalize on the recently solved atomic-resolution structure for a GluA2 tetrameric receptor, a NMDA receptor homologue and our growing expertise on NMDA receptor gating modulation. We will introduce mutations to perturb (increase and decrease) the relative mobility of NMDA receptor structural modules and will delineate the accompanying changes in reaction mechanism by kinetic analyses of single-molecule signals. Further, we will explore the time course of macroscopic responses obtained from receptors with restricted or enhanced internal motions to better understand how specific structural features support the unique biological functions played by NMDA receptors in brain physiology and pathology. Overall this work will provide critical information about structural correlates of NMDA receptor activation and will integrate the currently isolated structural and kinetic models of gating. Given that glutamate receptors mediate more than 90% of excitatory transmission in brain and NMDA receptors are critical to many fundamental brain functions, knowledge generated by the proposed experiments is likely to have wide impact on the fields of neurotransmission and neuromodulation. PUBLIC HEALTH RELEVANCE: NMDA receptors mediate fundamental brain processes and are therapeutic target for a number of neuropathologies including stroke, chronic neurodegeneration, addiction and pain. Results from this application will provide needed information about structural correlates of NMDA receptor activation and by integrating structural and kinetic models of gating will assist in the rational design of pharmacologic approaches to address acute and chronic neuropathies.