兴奋-收缩耦联过程蛋白质复合体的结构与功能调控

肌细胞由兴奋导致收缩的过程称为兴奋-收缩耦联。Ryanodine 受体（RyR）在兴奋-收缩耦联过程中起至关重要的核心作用。RyR功能异常，常常导致严重疾病，如神经系统疾病、代谢综合征和心脏病。RyR因此成为治疗这些疾病的关键靶标。骨骼肌RyR1与细胞膜上钙通道DHPR形成RyR1-DHPR复合体，在兴奋-收缩耦联中起核心作用；RyR与多个调节蛋白形成RyR-调节蛋白复合体，调节RyR通道的功能和兴奋-收缩耦联。DHPR-RyR1耦联及调节蛋白调节RyR1功能的结构基础及工作机制尚不清楚。我们在基金委面上项目支持下，应用冷冻电镜成功的解析了RyR1关闭态和开放态的高分辨三维结构。本项目将应用冷冻电镜研究RyR1-DHPR和RyR1-调节蛋白复合体的高分辨三维结构, 结合生物化学和电生理学，阐明DHPR-RyR1耦联和调节蛋白与RyR相互作用并调节RyR/钙释放通道的结构基础和工作机制。

Excitation-contraction coupling is the process of excitation leading to contraction of muscle cells. Ryanodine receptor (RyR) plays a critical central role during excitation-contraction (E-C) coupling. The RyR is activated upon receiving an excitation signal and release Ca2+ from sarcoplasmic reticulum into cytosol, leading to contraction of muscle cells. The dysfunction of RyR would result in vital diseases, such as neurodegenerative diseases, metabolic syndrome and heart diseases. RyR is the key target for drug development to treat these diseases. In situ, skeletal RyR1 interacts with surface membrane calcium channel DHPR, forming RyR1-DHPR complex，which play a key role in E-C coupling; a variety of regulatory proteins, forming RyR-regulatory protein complexes and regulating its channel function and E-C coupling. The structural basis and action mechanisms of RyR1-DHPR coupling and the regulation of RyR1 function by regulatory proteins, however, are not known. Supported by the NSFC from the project previously granted, we successfully solved the closed-state and open-state structures of RyR1 to high-resolution. In this project, we propose to solve the high-resolution structures of RyR1-DHPR and RyR1-regulatory protein complexes by cryo-electron microscopy, combining with biochemical and electrophysiological studies, to elucidate the structural basis and action mechanisms of RyR1-DHPR coupling and the regulation of RyR1 function by regulatory proteins.