TMC1 and TMC2 Localize at the Site of Mechanotransduction in Mammalian Inner Ear Hair Cell Stereocilia

Kiyoto Kurima; Seham Ebrahim; Bifeng Pan; Miloslav Sedlacek; Prabuddha Sengupta; Bryan A. Millis; Runjia Cui; Hiroshi Nakanishi; Taro Fujikawa; Yoshiyuki Kawashima; Byung Yoon Choi; Kelly Monahan; Jeffrey R. Holt; Andrew J. Griffith; Bechara Kachar

doi:10.1016/j.celrep.2015.07.058

Cell Reports (Sep 2015)

TMC1 and TMC2 Localize at the Site of Mechanotransduction in Mammalian Inner Ear Hair Cell Stereocilia

Kiyoto Kurima,
Seham Ebrahim,
Bifeng Pan,
Miloslav Sedlacek,
Prabuddha Sengupta,
Bryan A. Millis,
Runjia Cui,
Hiroshi Nakanishi,
Taro Fujikawa,
Yoshiyuki Kawashima,
Byung Yoon Choi,
Kelly Monahan,
Jeffrey R. Holt,
Andrew J. Griffith,
Bechara Kachar

Affiliations

Kiyoto Kurima: Molecular Biology and Genetics Section, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA
Seham Ebrahim: Laboratory of Cell Structure and Dynamics, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA
Bifeng Pan: Department of Otolaryngology, F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
Miloslav Sedlacek: Laboratory of Cell Structure and Dynamics, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA
Prabuddha Sengupta: Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA
Bryan A. Millis: Laboratory of Cell Structure and Dynamics, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA
Runjia Cui: Laboratory of Cell Structure and Dynamics, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA
Hiroshi Nakanishi: Molecular Biology and Genetics Section, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA
Taro Fujikawa: Laboratory of Cell Structure and Dynamics, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA
Yoshiyuki Kawashima: Molecular Biology and Genetics Section, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA
Byung Yoon Choi: Section on Human Genetics, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA
Kelly Monahan: Molecular Biology and Genetics Section, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA
Jeffrey R. Holt: Department of Otolaryngology, F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
Andrew J. Griffith: Molecular Biology and Genetics Section, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA
Bechara Kachar: Laboratory of Cell Structure and Dynamics, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA

DOI: https://doi.org/10.1016/j.celrep.2015.07.058
Journal volume & issue: Vol. 12, no. 10
pp. 1606 – 1617

Abstract

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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.

Published in Cell Reports

ISSN: 2211-1247 (Online)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Science: Biology (General)
Website: http://www.cell.com/cell-reports/home

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