State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, Beijing, China.
Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China.
Elife. 2021 Mar 8;10:e63429. doi: 10.7554/eLife.63429.
TRPC5 channel is a nonselective cation channel that participates in diverse physiological processes. TRPC5 inhibitors show promise in the treatment of anxiety disorder, depression, and kidney disease. However, the binding sites and inhibitory mechanism of TRPC5 inhibitors remain elusive. Here, we present the cryo-EM structures of human TRPC5 in complex with two distinct inhibitors, namely clemizole and HC-070, to the resolution of 2.7 Å. The structures reveal that clemizole binds inside the voltage sensor-like domain of each subunit. In contrast, HC-070 is wedged between adjacent subunits and replaces the glycerol group of a putative diacylglycerol molecule near the extracellular side. Moreover, we found mutations in the inhibitor binding pockets altered the potency of inhibitors. These structures suggest that both clemizole and HC-070 exert the inhibitory functions by stabilizing the ion channel in a nonconductive closed state. These results pave the way for further design and optimization of inhibitors targeting human TRPC5.
TRPC5 通道是一种非选择性阳离子通道，参与多种生理过程。TRPC5 抑制剂在治疗焦虑症、抑郁症和肾病方面显示出前景。然而，TRPC5 抑制剂的结合位点和抑制机制仍不清楚。在这里，我们呈现了人源 TRPC5 与两种不同抑制剂（即克立莫唑和 HC-070）复合物的冷冻电镜结构，分辨率达到 2.7Å。这些结构揭示了克立莫唑结合在每个亚基的电压传感器样结构域内。相比之下，HC-070 位于相邻亚基之间，并取代了细胞外侧附近假定的二酰基甘油分子中甘油基团。此外，我们发现抑制剂结合口袋中的突变改变了抑制剂的效力。这些结构表明，克立莫唑和 HC-070 都通过将离子通道稳定在非传导的关闭状态来发挥抑制作用。这些结果为进一步设计和优化针对人源 TRPC5 的抑制剂铺平了道路。
