Enables proton channel activity. Involved in cellular response to insulin stimulus; negative regulation of interferon-gamma-mediated signaling pathway; and proton transmembrane transport. Acts upstream of or within detection of gravity and inner ear morphogenesis. Located in membrane. Is integral component of plasma membrane. Is expressed in several structures, including adrenal gland; inner ear; integumental system; stomach; and thymus. Orthologous to human OTOP1 (otopetrin 1). [provided by Alliance of Genome Resources, Apr 2022]