Departments of Biophysics and Neurosurgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P. R. China.
Departments of Biophysics and Pathology of Sir Run 14, Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310058, P. R. China.
Cell Rep. 2021 Nov 16;37(7):110025. doi: 10.1016/j.celrep.2021.110025.
Transient receptor potential melastatin 2 (TRPM2), a Ca-permeable cation channel, is gated by intracellular adenosine diphosphate ribose (ADPR), Ca, warm temperature, and oxidative stress. It is critically involved in physiological and pathological processes ranging from inflammation to stroke to neurodegeneration. At present, the channel's gating and ion permeation mechanisms, such as the location and identity of the selectivity filter, remain ambiguous. Here, we report the cryo-electron microscopy (cryo-EM) structure of human TRPM2 in nanodisc in the ligand-free state. Cryo-EM map-guided computational modeling and patch-clamp recording further identify a quadruple-residue motif as the ion selectivity filter, which adopts a restrictive conformation in the closed state and acts as a gate, profoundly contrasting with its widely open conformation in the Nematostella vectensis TRPM2. Our study reveals the gating of human TRPM2 by the filter and demonstrates the feasibility of using cryo-EM in conjunction with computational modeling and functional studies to garner structural information for intrinsically dynamic but functionally important domains.
瞬时受体电位阳离子通道亚家族 M 成员 2（TRPM2）是一种钙离子通透性阳离子通道，由细胞内二磷酸腺苷核糖（ADPR）、钙离子、温度升高和氧化应激激活。它在从炎症到中风到神经退行性变等生理和病理过程中起着关键作用。目前，该通道的门控和离子渗透机制，如选择性过滤器的位置和身份，仍然不清楚。在这里，我们报告了无配体状态下人源 TRPM2 在纳米盘中的冷冻电镜（cryo-EM）结构。冷冻电镜图谱引导的计算建模和膜片钳记录进一步确定了一个四残基基序作为离子选择性过滤器，它在关闭状态下采用限制构象，充当门，与 Nematostella vectensis TRPM2 中的广泛开放构象形成鲜明对比。我们的研究揭示了人源 TRPM2 的门控由过滤器控制，并证明了使用冷冻电镜结合计算建模和功能研究来获取对内在动态但功能重要的结构域的结构信息的可行性。
