PDZD7-MYO7A complex identified in enriched stereocilia membranes
Clive P Morgan,
Jocelyn F Krey,
M'hamed Grati,
Bo Zhao,
Shannon Fallen,
Abhiraami Kannan-Sundhari,
Xue Zhong Liu,
Dongseok Choi,
Ulrich Müller,
Peter G Barr-Gillespie
Affiliations
Clive P Morgan
Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, United States
Jocelyn F Krey
Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, United States
M'hamed Grati
Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, United States
Bo Zhao
Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, United States
Shannon Fallen
Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, United States
Abhiraami Kannan-Sundhari
Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, United States
Xue Zhong Liu
Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, United States
Dongseok Choi
OHSU-PSU School of Public Health, Oregon Health and Science University, Portland, United States; Graduate School of Dentistry, Kyung Hee University, Seoul, Korea
Ulrich Müller
Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, United States
While more than 70 genes have been linked to deafness, most of which are expressed in mechanosensory hair cells of the inner ear, a challenge has been to link these genes into molecular pathways. One example is Myo7a (myosin VIIA), in which deafness mutations affect the development and function of the mechanically sensitive stereocilia of hair cells. We describe here a procedure for the isolation of low-abundance protein complexes from stereocilia membrane fractions. Using this procedure, combined with identification and quantitation of proteins with mass spectrometry, we demonstrate that MYO7A forms a complex with PDZD7, a paralog of USH1C and DFNB31. MYO7A and PDZD7 interact in tissue-culture cells, and co-localize to the ankle-link region of stereocilia in wild-type but not Myo7a mutant mice. Our data thus describe a new paradigm for the interrogation of low-abundance protein complexes in hair cell stereocilia and establish an unanticipated link between MYO7A and PDZD7.
