The invention provides isolated nucleic acids molecules, designated COCH5B2 nucleic acid molecules, which encode polypeptides involved in inner ear biology. The invention also provides antisense nucleic acid molecules, expression vectors containing COCH5b2 nucleic acid molecules, host cells into which the expression vectors have been introduced, and non-human transgenic animals in which a COCH5b2 gene has been introduced or disrupted. The invention still further provides isolated COCH5B2 polypeptides, fusion polypeptides, antigenic peptides, and anti-COCH5B2 antibodies. Diagnostic, screening, and therapeutic methods utilizing compositions of the invention are also provided.