Mechanism of calcium potentiation of alpha7 nicotinic receptors

项目摘要-7尼古丁受体广泛分布于人脑，并且 丰富了认知、感觉处理、注意力、工作记忆和奖励所需的区域。他们 与阿尔茨海默氏症和帕金森氏症等神经退行性疾病以及精神疾病有关 精神分裂症等疾病，以及注意力和认知障碍。7受体也存在于 非神经细胞参与多种抗炎途径。该计划的总体目标 拟议的研究旨在从机制上理解7受体的激活和调节 适用于治疗性药物设计。这项提案将研究钙是如何增强7尼古丁的 受体被生理上占优势的低浓度激动剂激活。我们已经开发了一种联合- 激动剂假说不仅可以解释7在远离胆碱能神经的情况下是如何发出信号的 但这也表明与神经元放电相关的钙波动调节7信号转导。至 研究7的钙增敏作用，将用X射线结晶学方法测定原子 与增强离子钙和钡结合的7配体结合域的分辨结构。在……里面 平行的单分子电生理方法将定义二价离子背后的动力学机制 增强功能。最后，分子生物学和单分子电生理方法的应用将 鉴定7中介导二价阳离子增强的氨基酸残基，并测定化学计量比 二价阳离子通过它来增强。该项目的完成将揭示 适用于神经系统疾病治疗和治疗药物的-7的激活和钙调节 设计。

PROJECT SUMMARY- 7 nicotinic receptors are widely distributed throughout the human brain, and are enriched in regions required for cognition, sensory processing, attention, working memory and reward. They have been implicated in neurodegenerative diseases such as Alzheimer’s and Parkinson’s and psychiatric diseases such as schizophrenia, and disorders of attention and cognition. 7 receptors are also present in non-neuronal cells where they contribute to a variety of anti-inflammatory pathways. The overall goal of the proposed research is to develop a mechanistic understanding of activation and modulation of 7 receptors applicable to therapeutic drug design. This proposal will investigate how calcium potentiates 7 nicotinic receptors activated by the low agonist concentrations that prevail physiologically. We have developed a co- agonist hypothesis that not only can explain how 7 signals despite being far from cholinergic nerve terminals, but it also suggests calcium fluctuations associated with neuronal firing regulate 7 signaling. To investigate calcium potentiation of 7, X-ray crystallographic methods will be used to determine atomic resolution structures of an 7 ligand binding domain bound with the potentiating ions calcium and barium. In parallel, single molecule electrophysiological methods will define the kinetic mechanism behind divalent ion potentiation. Finally, application of molecular biological and single molecule electrophysiological methods will identify amino acid residues in 7 that mediate divalent cation potentiation, and determine the stoichiometry with which divalent cations potentiate. Completion of this project will reveal mechanistic underpinnings of activation and calcium regulation of 7 applicable to neurological disease treatment and therapeutic drug design.