alpha7 nicotinic acetylcholine receptor allosteric modulation and native structure

项目概要/摘要： 烟碱型乙酰胆碱受体是负责兴奋性乙酰胆碱受体的五聚体配体门控离子通道。 在整个神经系统中传递信号α7烟碱受体亚型是广泛表达的亚型， 在烟碱受体中是独特的，因为它形成功能性同五聚体，迅速脱敏， 对Ca 2+的渗透性非常好。它在人类疾病中起着重要作用，与α7相关的调节异常， 阿尔茨海默病、精神分裂症和炎症。α7的独特特性和疾病的参与 已经使其成为一个有吸引力的治疗靶点，导致开发了许多旨在 增强α7活性。其中最有前途的策略是正变构调节剂（PAM）。PAMS 增加受体活性，同时保持内源性的空间和时间特征， 神经传递尽管功能表征很强，但精确的调节剂结合位点和结构 增强作用的机制仍然未知，这是合理药物设计的主要障碍。 此外，虽然α7可以独特地组装为功能性同源五聚体，但它也可以与其他同源五聚体结合。 亚型形成异聚体，产生增加的多样性和改变的通道特性。α7度 天然组织中的通道多样性尚不清楚。因此，该应用程序的主要目标是解决关键问题 通过阐明受体调节机制和确定与α7亚型相关的分子机制， 天然α7的结构。在以前定义主要门控循环构象的工作的基础上，我的目标是确定 α7与多种别构调节剂复合的高分辨率结构。与此同时，我将开发一个 从脑组织中纯化天然α7并使用单克隆抗体测定含α7通道的结构的方法 粒子冷冻电镜总之，这项工作将确定受体调节和天然α7 结构和亚基化学计量，增强我们对α7生物学和药理学的理解。此外，委员会认为， 这项工作将为未来天然受体的纯化和药物开发提供基础， 整个烟碱受体家族。

Project Summary/Abstract: Nicotinic acetylcholine receptors are pentameric ligand-gated ion channels responsible for excitatory signaling throughout the nervous system. The α7 nicotinic receptor subtype is a widely expressed subtype that is unique among nicotinic receptors in that it forms a functional homopentamer, desensitizes rapidly, and is exceptionally permeable to Ca2+. It plays a prominent role in human disease with dysregulation of α7 linked to Alzheimer’s disease, schizophrenia, and inflammation. α7’s unique characteristics and involvement in disease have made it an attractive therapeutic target leading to the development of numerous compounds aimed at enhancing α7 activity. Among the most promising strategies are positive allosteric modulators (PAMs). PAMs increase receptor activity while maintaining the spatial and temporal characteristics of endogenous neurotransmission. Despite strong functional characterization, precise modulator binding sites and structural mechanisms of potentiation remain unknown, representing a major roadblock towards rational drug design. Moreover, while α7 can uniquely assemble as a functional homopentamer, it can also associate with other subtypes forming a heteromer, yielding increased diversity and altered channel properties. The degree of α7 channel diversity in native tissue is unclear. Thus, the major goal of this application is to resolve key questions related to the α7 subtype by elucidating receptor modulation mechanisms and determining the molecular structure of native α7. Building on previous work defining major gating cycle conformations, I aim to determine high resolution structures of α7 complexed with numerous allosteric modulators. In parallel, I will develop a method to purify native α7 from brain tissue and determine the structure of α7-containing channels using single particle cryo-EM. Taken together, this work will define mechanisms of receptor modulation and native α7 structure and subunit stoichiometry, enhancing our understanding of α7 biology and pharmacology. Furthermore, this work will provide a foundation for future native receptor purification and aid drug development towards the entire nicotinic receptor family.