Essential for hearing (By similarity). Required for maintenance of stereocilia on both inner and outer hair cells (By similarity). Necessary for the integrity of the stereociliary rootlet (By similarity). May act as an actin cytoskeleton regulator involved in the regulation of actin dynamics at the pointed end in hair cells (By similarity). Forms rings at the base of stereocilia and binds actin filaments in the stereocilia which may stabilize the stereocilia (By similarity). Acts as a strong inhibitor of PPP1CA phosphatase activity (PubMed:23213405). Recruited to sites of DNA damage and may play a role in DNA damage repair (PubMed:23213405). {ECO:0000250|UniProtKB:A2AI08, ECO:0000269|PubMed:23213405}. This is the function of TPRN (taperin, ENSG00000176058).