Mediates voltage-dependent potassium ion permeability of excitable membranes. Assuming opened or closed conformations in response to the voltage difference across the membrane, the protein forms a potassium-selective channel through which potassium ions may pass in accordance with their electrochemical gradient. The channel activity is up-regulated by cAMP. Homotetramer. Interacts with KCN4B/POMP. Interaction with KCN4B/POMP is necessary for the modulation of channel activity by cAMP. Expressed strongly in the inner ear and weakly in skeletal muscle. Not detected in other tissues. Detected in the cochlear duct from 14.5 dpc (PubMed:22446089). Detected in the organ of Corti and the vestibular system from 16.5 dpc onwards, where it is most strongly expressed in hair cells (PubMed:22446089, PubMed:23528307). The N-terminus may be important in determining the rate of inactivation of the channel while the tail may play a role in modulation of channel activity and/or targeting of the channel to specific subcellular compartments. The segment S4 is probably the voltage-sensor and is characterized by a series of positively charged amino acids at every third position. Viable with no gross defects. Vestibular evoked potentials (VsEPs) are highly abnormal suggesting impaired function of the balance organ, although mice do not display any obvious imbalance behaviors. Belongs to the potassium channel family. A (Shaker) (TC 1.A.1.2) subfamily. Kv1.8/KCNA10 sub-subfamily.