ジャーナル: Nature / 年: 2024 タイトル: Mechanical activation opens a lipid-lined pore in OSCA ion channels. 著者: Yaoyao Han / Zijing Zhou / Ruitao Jin / Fei Dai / Yifan Ge / Xisan Ju / Xiaonuo Ma / Sitong He / Ling Yuan / Yingying Wang / Wei Yang / Xiaomin Yue / Zhongwen Chen / Yadong Sun / Ben Corry / ...著者: Yaoyao Han / Zijing Zhou / Ruitao Jin / Fei Dai / Yifan Ge / Xisan Ju / Xiaonuo Ma / Sitong He / Ling Yuan / Yingying Wang / Wei Yang / Xiaomin Yue / Zhongwen Chen / Yadong Sun / Ben Corry / Charles D Cox / Yixiao Zhang / 要旨: OSCA/TMEM63 channels are the largest known family of mechanosensitive channels, playing critical roles in plant and mammalian mechanotransduction. Here we determined 44 cryogenic electron microscopy ...OSCA/TMEM63 channels are the largest known family of mechanosensitive channels, playing critical roles in plant and mammalian mechanotransduction. Here we determined 44 cryogenic electron microscopy structures of OSCA/TMEM63 channels in different environments to investigate the molecular basis of OSCA/TMEM63 channel mechanosensitivity. In nanodiscs, we mimicked increased membrane tension and observed a dilated pore with membrane access in one of the OSCA1.2 subunits. In liposomes, we captured the fully open structure of OSCA1.2 in the inside-in orientation, in which the pore shows a large lateral opening to the membrane. Unusually for ion channels, structural, functional and computational evidence supports the existence of a 'proteo-lipidic pore' in which lipids act as a wall of the ion permeation pathway. In the less tension-sensitive homologue OSCA3.1, we identified an 'interlocking' lipid tightly bound in the central cleft, keeping the channel closed. Mutation of the lipid-coordinating residues induced OSCA3.1 activation, revealing a conserved open conformation of OSCA channels. Our structures provide a global picture of the OSCA channel gating cycle, uncover the importance of bound lipids and show that each subunit can open independently. This expands both our understanding of channel-mediated mechanotransduction and channel pore formation, with important mechanistic implications for the TMEM16 and TMC protein families.