title: TMC1 and TMC2 Localize at the Site of Mechanotransduction in Mammalian Inner Ear Hair Cell Stereocilia.
abstract: 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 Tmc1(Δ/Δ);Tmc2(Δ/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.
authors: Molecular Biology and Genetics Section, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA.
authors: Kiyoto
authors: K
authors: Kurima
authors: Laboratory of Cell Structure and Dynamics, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA.
authors: Seham
authors: S
authors: Ebrahim
authors: Department of Otolaryngology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
authors: Bifeng
authors: B
authors: Pan
authors: Laboratory of Cell Structure and Dynamics, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA.
authors: Miloslav
authors: M
authors: Sedlacek
authors: Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA.
authors: Prabuddha
authors: P
authors: Sengupta
authors: Laboratory of Cell Structure and Dynamics, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA.
authors: Bryan A
authors: BA
authors: Millis
authors: Laboratory of Cell Structure and Dynamics, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA.
authors: Runjia
authors: R
authors: Cui
authors: Molecular Biology and Genetics Section, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA.
authors: Hiroshi
authors: H
authors: Nakanishi
authors: Laboratory of Cell Structure and Dynamics, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA.
authors: Taro
authors: T
authors: Fujikawa
authors: Molecular Biology and Genetics Section, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA.
authors: Yoshiyuki
authors: Y
authors: Kawashima
authors: Molecular Biology and Genetics Section, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA.
authors: Byung Yoon
authors: BY
authors: Choi
authors: Molecular Biology and Genetics Section, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA.
authors: Kelly
authors: K
authors: Monahan
authors: Department of Otolaryngology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
authors: Jeffrey R
authors: JR
authors: Holt
authors: Molecular Biology and Genetics Section, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA,. Electronic address: griffita@nidcd.nih.gov.
authors: Andrew J
authors: AJ
authors: Griffith
authors: Laboratory of Cell Structure and Dynamics, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA,. Electronic address: kacharb@nidcd.nih.gov.
authors: Bechara
authors: B
authors: Kachar
mesh_terms: D000818:Animals; D002923:Cilia / Q000378:metabolism* / Q000648:ultrastructure; D005260:Female; D015870:Gene Expression; D006199:Hair Cells, Auditory, Inner / Q000502:physiology* / Q000648:ultrastructure; D008297:Male; D040542:Mechanotransduction, Cellular; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008822:Mice, Transgenic; D021381:Protein Transport
chemical_list: D008565:Membrane Proteins; C514628:TMC1 protein, mouse; C575755:TMC2 protein, mouse