Neuron
Volume 84, Issue 5, 3 December 2014, Pages 954-967
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Article
TMIE Is an Essential Component of the Mechanotransduction Machinery of Cochlear Hair Cells

https://doi.org/10.1016/j.neuron.2014.10.041Get rights and content
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Highlights

  • TMIE is essential for mechanotransduction by hair cells

  • TMIE binds to components of the tip-link complex

  • Interactions of TMIE with tip links are critical for transduction

  • The mechanotransduction machinery of hair cells is a multisubunit molecular machine

Summary

Hair cells are the mechanosensory cells of the inner ear. Mechanotransduction channels in hair cells are gated by tip links. The molecules that connect tip links to transduction channels are not known. Here we show that the transmembrane protein TMIE forms a ternary complex with the tip-link component PCDH15 and its binding partner TMHS/LHFPL5. Alternative splicing of the PCDH15 cytoplasmic domain regulates formation of this ternary complex. Transducer currents are abolished by a homozygous Tmie-null mutation, and subtle Tmie mutations that disrupt interactions between TMIE and tip links affect transduction, suggesting that TMIE is an essential component of the hair cell’s mechanotransduction machinery that functionally couples the tip link to the transduction channel. The multisubunit composition of the transduction complex and the regulation of complex assembly by alternative splicing is likely critical for regulating channel properties in different hair cells and along the cochlea’s tonotopic axis.

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Present address: Department of Otolaryngology, Stanford University, 300 Pasteur Drive, Stanford, CA 94305, USA