CHRNA9 is a member of the ligand-gated ionic channel family and nicotinic acetylcholine receptor gene superfamily. It encodes a plasma membrane protein that forms homo- or hetero-oligomeric divalent cation channels. This protein is involved in cochlea hair cell development and is also expressed in the outer hair cells (OHCs) of the adult cochlea. The protein is additionally expressed in keratinocytes, the pituitary gland, B-cells and T-cells. [provided by RefSeq]