Auditory hair cells receive olivocochlear efferent innervation, which refines tonotopic mapping, improves sound discrimination, and mitigates acoustic trauma. The olivocochlear synapse involves α9α10 nicotinic acetylcholine receptors (nAChRs), which assemble in hair cells only coincident with cholinergic innervation and do not express in recombinant mammalian cell lines. Here, genome-wide screening determined that assembly and surface expression of α9α10 require ligand binding. Ion channel function additionally demands an auxiliary subunit, which can be transmembrane inner ear (TMIE) or TMEM132e. Both of these single-pass transmembrane proteins are enriched in hair cells and underlie nonsyndromic human deafness. Inner hair cells from TMIE mutant mice show altered postsynaptic α9α10 function and retain α9α10-mediated transmission beyond the second postnatal week associated with abnormally persistent cholinergic innervation. Collectively, this study provides a mechanism to link cholinergic input with α9α10 assembly, identifies unexpected functions for human deafness genes TMIE/TMEM132e, and enables drug discovery for this elusive nAChR implicated in prevalent auditory disorders.

听觉毛细胞接受小耳神经传出神经支配，从而改善了音位映射，改善了声音辨别力，减轻了听觉创伤。少核突触涉及α9α10烟碱乙酰胆碱受体（nAChRs），其在毛细胞中的组装仅与胆碱能神经支配相符，而在重组哺乳动物细胞系中不表达。在这里，全基因组筛选确定α9α10的组装和表面表达需要配体结合。离子通道功能还需要一个辅助子单元，该子单元可以是跨膜内耳（TMIE）或TMEM132e。这两种单程跨膜蛋白均富含毛细胞，是人类非综合征性耳聋的基础。TMIE突变小鼠的内部毛细胞显示出突触后α9α10功能的改变，并在与异常持续的胆碱能神经支配相关的产后第二周后保留了α9α10介导的传递。总的来说，这项研究提供了一种机制，将胆碱能输入与α9α10组装相关联，确定了人类耳聋基因TMIE / TMEM132e的意外功能，并为涉及普遍听觉障碍的这种难以捉摸的nAChR发现了药物。