Hair cell bundles consist of stereocilia arranged in rows of increasing heights, connected by tip links that transmit sound-induced forces to shorter stereocilia tips. Auditory mechanotransduction channel complexes, composed of proteins TMC1/2, TMIE, CIB2, and LHFPL5, are located at the tips of shorter stereocilia. While most components can interact with the tip link in vitro, their ability to maintain the channel complexes at the tip link in vivo is uncertain. Return, using mouse models, we show that an additional component, LOXHD1, is essential for keeping TMC1-pore forming subunits at the tip link but is dispensable for TMC2. Using SUB-immunogold-SEM, we showed that TMC1 localizes near the tip link but mislocalizes without LOXHD1. LOXHD1 selectively interacts with TMC1, CIB2, LHFPL5, and tip-link protein PCDH15. Our results demonstrate that TMC1-driven mature auditory channels require LOXHD1 to stay connected to the tip link and remain functional, while TMC2-driven developmental channels do not.

毛细胞束由成行排列的立体纤毛组成，通过尖端链接连接，这些尖端链接将声音诱导的力传递到较短的立体纤毛尖端。由蛋白质 TMC1/2 、 TMIE、CIB2 和 LHFPL5 组成的听觉机械转导通道复合物位于较短立体纤毛的尖端。虽然大多数组分可以在体外与 tip link 相互作用，但它们在体内维持 tip link 处的通道复合物的能力是不确定的。返回，使用小鼠模型，我们表明另一种成分 LOXHD1 对于将 TMC1 成孔亚基保持在尖端链接处是必不可少的，但对于 TMC2 来说可有可无。使用 SUB-immunogold-SEM，我们发现 TMC1 定位在尖端连接附近，但在没有 LOXHD1 的情况下定位错误。LOXHD1 选择性地与 TMC1、CIB2、LHFPL5 和 tip-link 蛋白 PCDH15 相互作用。我们的结果表明，TMC1 驱动的成熟听觉通道需要 LOXHD1 保持与尖端链接的连接并保持功能，而 TMC2 驱动的发育通道则不需要。