The KCNQ family of voltage-gated K+ channels includes 5 known members: KCNQ1 to KCNQ5. Structurally, the KCNQ family belongs to the six transmembrane domain category of K+ channels. KCNQ family members can form either homomultimeric or heteromultimeric channels with different functional consequences. For example KCNQ2 and KCNQ3 heteromultimers give rise to a much larger channel current than when either protein is expressed alone, probably due to enhanced plasma membrane expression of the combined channel. Indeed, KCNQ2/KCNQ3 heteromultimers are believed to be the molecular correlates of the so-called M current. This current is a K+ neuronal current that is strongly inhibited by the activation of the M1 subtype of the muscarinic acetylcholine receptor. nnMutations in either KCNQ2 or KCNQ3 are associated with a form of epilepsy known as benign familial neonatal convulsions (BNFC).
