Data from: Mechanotransduction current is essential for stability of the transducing stereocilia in mammalian auditory hair cells

Mechanotransducer channels at the tips of sensory stereocilia of inner ear hair cells are gated by the tension of 'tip links' interconnecting stereocilia. To ensure maximal sensitivity, tip links are tensioned at rest, resulting in a continuous influx of Ca2+ into the cell. Here we show that this constitutive Ca2+ influx, usually considered as potentially deleterious for hair cells, is in fact essential for stereocilia stability. In the auditory hair cells of young postnatal mice and rats, a reduction in mechanotransducer current, via pharmacological channel blockers or disruption of tip links, leads to stereocilia shape changes and shortening. These effects occur only in stereocilia that harbor mechanotransducer channels, recover upon blocker washout or tip link regeneration, and can be replicated by manipulations of extracellular Ca2+ or intracellular Ca2+ buffering. Thus, our data provide the first experimental evidence for the dynamic control of stereocilia morphology by the mechanotransduction current.

内耳毛细胞感觉静纤毛（sensory stereocilia）尖端的机械转导通道（mechanotransducer channels），由连接静纤毛的“顶链接（tip links）”的张力进行门控。为保障最优感知灵敏度，顶链接在静息状态下便维持张紧状态，由此引发钙离子（Ca²+）持续内流入细胞。本研究证实，这种通常被认为可能对毛细胞产生损害的组成型钙离子内流，实则对静纤毛的稳定性不可或缺。在新生小鼠与幼年大鼠的听觉毛细胞中，通过使用药理学通道阻滞剂阻断或破坏顶链接以降低机械转导电流，会引发静纤毛形态改变及缩短。上述效应仅发生在承载机械转导通道的静纤毛中，可在阻滞剂洗脱或顶链接再生后完全恢复，且可通过调控细胞外钙离子或细胞内钙离子缓冲手段复现。综上，本研究数据首次通过实验证实，机械转导电流可动态调控静纤毛的形态结构。