Probably important in the regulation of neuronal excitability. May underlie a potassium current involved in regulating the excitability of sensory cells of the cochlea. Homotetramer. May form heteromultimers with KCNQ3 (By similarity). Interacts with HSP90AB1; promotes cell surface expression of KCNQ4 (By similarity). Situated at the basal membrane of cochlear outer hair cells. In the inner ear expressed in the outer sensory hair cells of the cochlea and in type I hair cells of the vestibular organs. Also expressed in the postsynaptic membrane of the calyx nerve endings innervating type I cells. In the brain expressed in neurons of many, but not all, nuclei of the central auditory pathway. Absent from most other brain regions. The segment S4 is probably the voltage-sensor and is characterized by a series of positively charged amino acids at every third position. The A-domain tail carries the major determinants of channel assembly specificity. Its coiled-coil region is Four-stranded (By similarity). Belongs to the potassium channel family. KQT (TC 1.A.1.15) subfamily. Kv7.4/KCNQ4 sub-subfamily.