Stereocilia-staircase spacing is influenced by myosin III motors and their cargos espin-1 and espin-like

Authors

Seham Ebrahim, National Institutes of Health, Bethesda, Maryland
Matthew R. Avenarius, Oregon Health & Science University, Portland
M’hamed Grati, National Institutes of Health, Bethesda, Maryland
Jocelyn F. Krey, Oregon Health & Science University, Portland
Alanna M. Windsor, National Institutes of Health, Bethesda, Maryland
Aurea D. Sousa, National Institutes of Health, Bethesda, Maryland
Angela Ballesteros, National Institutes of Health, Bethesda, Maryland
Runjia Cui, National Institutes of Health, Bethesda, Maryland
Bryan A. Millis, National Institutes of Health, Bethesda, Maryland
Felipe T. Salles, National Institutes of Health, Bethesda, Maryland
Michelle A. Baird, Florida State University, Tallahassee
Michael W. Davidson, Florida State University, Tallahassee
Sherri M. Jones, University of Nebraska-LincolnFollow
Dongseok Choi, Oregon Health and Science University, PortlandFollow
Lijin Dong, National Institutes of Health, Bethesda, Maryland
Manmeet H. Raval, Penn State University College of Medicine
Christopher M. Yengo, Penn State University College of Medicine
Peter G. Barr- Gillespie, Oregon Health & Science University, PortlandFollow
Bechara Kachar, National Institutes of Health, Bethesda, MarylandFollow

Document Type

Article

Date of this Version

2016

Citation

NATURE COMMUNICATIONS | 7:10833 | DOI: 10.1038/ncomms10833

Comments

This work is licensed under a Creative Commons Attribution 4.0 International License

Abstract

Hair cells tightly control the dimensions of their stereocilia, which are actin-rich protrusions with graded heights that mediate mechanotransduction in the inner ear. Two members of the myosin-III family, MYO3A and MYO3B, are thought to regulate stereocilia length by transporting cargos that control actin polymerization at stereocilia tips. We show that eliminating espin-1 (ESPN-1), an isoform of ESPN and a myosin-III cargo, dramatically alters the slope of the stereocilia staircase in a subset of hair cells. Furthermore, we show that espin-like (ESPNL), primarily present in developing stereocilia, is also a myosin-III cargo and is essential for normal hearing. ESPN-1 and ESPNL each bind MYO3A and MYO3B, but differentially influence how the two motors function. Consequently, functional properties of different motor-cargo combinations differentially affect molecular transport and the length of actin protrusions. This mechanism is used by hair cells to establish the required range of stereocilia lengths within a single cell.