Functions of Myosin VII in Mechanosensory Hair Cells

Project Summary
The long-term goal of our laboratories is to elucidate the mechanisms that control hair cell development and
function, and ascertain the defects in this process that cause deafness. We propose here to identify and study
proteins that physically and functionally interact with MYO7A and therefore mediate its function in hair cells.
Based on published and preliminary data, we hypothesize that MYO7A has a three-fold function in hair cells,
regulating the transport of proteins critical for hair bundle adhesion and actin polymerization and directly
controlling mechanotransduction. To test our hypothesis, we will: (i) define the protein complexes that mediate
stereocilia adhesion, focusing on those consisting of PCDH15 and GRP98; (ii) determine how MYO7A
complexes regulate stereocilia length, focusing initially on the complex with CAPZ that we have defined; (iii)
specify how MYO7A and its interacting proteins control mechanotransduction. Our preliminary data show the
feasibility of our approach. We have already identified hair bundle proteins that interact with MYO7A and
mediate its function. We anticipate that some of the novel interaction partners of MYO7A will be affected in
genetic diseases that cause hearing impairment.