Myosins are actin-based motor molecules with ATPase activity. Unconventional myosins serve in intracellular movements. Their highly divergent tails are presumed to bind to membranous compartments, which would be moved relative to actin filaments (By similarity). Required for the arrangement of stereocilia in mature hair bundles. Interacts with the third PDZ domain of WHRN which is necessary for localization of WHRN to stereocilium tips. Interacts with FASLG (By similarity). Interacts with EPS8. Localizes to stereocilium tips in cochlear and vestibular hair cells. In the developing inner ear, expressed in cochlea and vestibular apparatus. Expression appears to be restricted to cochlear neurosensory cells and upper epithelial layer of macula saccula. Also expressed in macula utriculi and cristae ampullaris of the semicircular canals. In adult cochlear hair cells, highest expression in stereocilia and apical body. Defects in Myo15a are the cause of shaker-2 (sh-2), a condition causing deafness, circling behavior, head tossing and hyperactivity. Auditory hair cells of affected animals have very short stereocilia and a long actin-containing protrusion at their basal end. Belongs to the TRAFAC class myosin-kinesin ATPase superfamily. Myosin family. Represents an unconventional myosin. This protein should not be confused with the conventional myosin-15 (MYH15).