Structural basis of nicotinic acetylcholine receptor gating and toxin inhibition

烟碱型乙酰胆碱受体是神经退行性疾病、成瘾和精神疾病的治疗靶点。 病这些五聚体配体门控离子通道是Cys环受体的原型成员 超家族，介导整个中枢和外周神经系统的快速神经传递。 关于烟碱受体生物物理学和药理学的基本问题仍然存在，这在很大程度上是由于 有限的高分辨率结构信息。我们建议确定高分辨率结构的两个 原型烟碱受体亚型，使用单粒子冷冻电子显微镜和研究结构- 基于分子动力学模拟和电生理学的机制假设。我们的第一个目标 肌肉型烟碱受体，五聚体受体超家族的创始成员。突变 该通道以及针对该受体的自身免疫抗体引起肌无力综合征。我们的第二 靶点是人α7烟碱受体。α7在烟碱受体中有几个方面是特殊的： 在生理学上组装为同型五聚体，它在大脑中大量表达，但也在非 作为一种电可兴奋的细胞类型，它对Ca 2+具有高渗透性，并且在微秒内脱敏。的 受体是神经退行性疾病、成瘾和炎症的靶点。我们建议使用单 结合诱变、电生理学和分子动力学的粒子冷冻电子显微镜 模拟阐明这两种细胞中通道激活、配体识别和离子渗透的机制， 不同的烟碱受体亚型，以确定一般机制和特异质性质。

Nicotinic acetylcholine receptors are therapeutic targets for neurodegenerative disorders, addiction, and mental illness. These pentameric ligand-gated ion channels are prototypical members of the Cys-loop receptor superfamily, which mediate fast neurotransmission throughout the central and peripheral nervous systems. Fundamental questions about nicotinic receptor biophysics and pharmacology remain, due in large part to the limited high-resolution structural information. We propose to determine high-resolution structures of two archetypal nicotinic receptor subtypes using single particle cryo-electron microscopy and investigate structure- based mechanistic hypotheses using molecular dynamics simulations and electrophysiology. Our first target is the muscle-type nicotinic receptor, the founding member of the pentameric receptor superfamily. Mutations in the channel, as well as autoimmune antibodies to the receptor, cause myasthenic syndromes. Our second target is the human α7 nicotinic receptor. α7 is exceptional among nicotinic receptors in several ways: it assembles physiologically as a homopentamer, it is expressed abundantly in the brain but also in non- electrically excitable cell types, it has a high permeability to Ca2+, and it desensitizes in microseconds. The receptor is a target in neurodegenerative disease, addiction and inflammation. We propose to use single particle cryo-electron microscopy combined with mutagenesis, electrophysiology and molecular dynamics simulations to elucidate mechanisms of channel activation, ligand recognition and ion permeation in these two distinctinctive nicotinic receptor subtypes to define general mechanisms and idiosyncratic properties.