TMC1 and TMC2 Proteins Are Pore-Forming Subunits of Mechanosensitive Ion Channels
TMC1 and TMC2 Proteins Are Pore-Forming Subunits of Mechanosensitive Ion Channels
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TMC1 和 TMC2 蛋白是机械敏感离子通道的成孔亚基。
DOI：
10.1016/j.neuron.2019.10.017
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发表时间：
2020-01-22
期刊：
影响因子：
16.2
通讯作者：
Yan, Zhiqiang
中科院分区：
文献类型：
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作者：
Jia, Yanyan;Zhao, Yimeng;Yan, Zhiqiang
跨膜通道样蛋白（TMC）1和2是小鼠内耳毛细胞机械转导所必需的，且定位于小鼠毛细胞静纤毛的机械转导位点。然而，TMC1和TMC2是否确实为离子通道，以及它们能否直接感知机械力，目前仍不清楚。在此，我们在昆虫细胞中表达绿海龟的TMC1（CmTMC1）和虎皮鹦鹉的TMC2（MuTMC2），对这些蛋白质进行纯化和重构，结果显示，脂质体重构的CmTMC1和MuTMC2蛋白具有离子通道活性。此外，通过对蛋白脂质体施加压力，我们证明CmTMC1和MuTMC2蛋白确实能够对机械刺激产生反应。另外，与人类听力损失突变相对应的CmTMC1突变体，其离子通道活性降低或丧失。综上所述，我们的研究结果表明，CmTMC1和MuTMC2蛋白是机械敏感离子通道的成孔亚基，支持TMC1和TMC2作为毛细胞转导通道的观点。
Transmembrane channel-like (TMC) 1 and 2 are required for the mechanotransduction of mouse inner ear hair cells and localize to the site of mechanotransduction in mouse hair cell stereocilia. However, it remains unclear whether TMC1 and TMC2 are indeed ion channels and whether they can sense mechanical force directly. Here we express TMC1 from the green sea turtle (CmTMC1) and TMC2 from the budgerigar (MuTMC2) in insect cells, purify and reconstitute the proteins, and show that liposome-reconstituted CmTMC1 and MuTMC2 proteins possess ion channel activity. Furthermore, by applying pressure to proteoliposomes, we demonstrate that both CmTMC1 and MuTMC2 proteins can indeed respond to mechanical stimuli. In addition, CmTMC1 mutants corresponding to human hearing loss mutants exhibit reduced or no ion channel activity. Taken together, our results show that the CmTMC1 and MuTMC2 proteins are poreforming subunits of mechanosensitive ion channels, supporting TMC1 and TMC2 as hair cell transduction channels.