TMC1 and TMC2 Localize at the Site of Mechanotransduction in Mammalian Inner Ear Hair Cell Stereocilia.
TMC1 and TMC2 Localize at the Site of Mechanotransduction in Mammalian Inner Ear Hair Cell Stereocilia.
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DOI：
10.1016/j.celrep.2015.07.058
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发表时间：
2015-09-08
期刊：
影响因子：
8.8
通讯作者：
Kachar B
中科院分区：
文献类型：
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作者：
Kurima K;Ebrahim S;Pan B;Sedlacek M;Sengupta P;Millis BA;Cui R;Nakanishi H;Fujikawa T;Kawashima Y;Choi BY;Monahan K;Holt JR;Griffith AJ;Kachar B
静纤毛尖端的机械敏感离子通道介导内耳感觉毛细胞中的机械电转导（MET）。跨膜通道样 1 和 2（TMC1 和 TMC2）对于 MET 至关重要，并被假设为 MET 复合体的组成部分，但缺乏预测它们在静纤毛中时空定位的证据。在这里，我们确定表达 TMC1-mCherry 和 TMC2-AcGFP 的小鼠中 TMC 蛋白的静纤毛定位。通过对 Tmc1Δ/Δ;Tmc2Δ/Δ 小鼠的 MET 电流和听力进行转基因拯救来验证标记蛋白的功能。 TMC1-mCherry 和 TMC2-AcGFP 沿着未成熟静纤毛的长度定位。然而，随着毛细胞的发育，这两种蛋白质主要定位于静纤毛尖端。最高的静纤毛的尖端不存在这两个 TMC，在那里检测不到 MET 活性。通过免疫荧光证实了内源蛋白的这种分布。这些数据与 TMC1 和 TMC2 是静纤毛 MET 通道复合体的组成部分一致。
Mechanosensitive ion channels at stereocilia tips mediate mechanoelectrical transduction (MET) in inner ear sensory hair cells. Transmembrane channel-like 1 and 2 (TMC1 and TMC2) are essential for MET and are hypothesized to be components of the MET complex, but evidence for their predicted spatiotemporal localization in stereocilia is lacking. Here we determine the stereocilia-localization of the TMC proteins in mice expressing TMC1-mCherry and TMC2-AcGFP. Functionality of the tagged proteins was verified by transgenic rescue of MET currents and hearing in Tmc1Δ/Δ;Tmc2Δ/Δ mice. TMC1-mCherry and TMC2-AcGFP localize along the length of immature stereocilia. However, as hair cells develop, the two proteins localize predominantly to stereocilia tips. Both TMCs are absent from the tips of the tallest stereocilia, where MET activity is not detectable. This distribution was confirmed for the endogenous proteins by immunofluorescence. These data are consistent with TMC1 and TMC2 being components of the stereocilia MET channel complex.