Pore-forming (alpha) subunit of voltage-gated potassium channel. Elicits a slowly activating, outward rectifying current (By similarity). Channel properties may be modulated by cAMP and subunit assembly (By similarity). The potassium channel is probably composed of a homo- or heterotetrameric complex of pore-forming alpha subunits that can associate with modulating beta subunits. The segment S4 is probably the voltage-sensor and is characterized by a series of positively charged amino acids at every third position. Belongs to the potassium channel family. H (Eag) (TC 1.A.1.20) subfamily. Kv12.1/KCNH8 sub-subfamily. There seems to be a problem in the assembly of the Mouse genome in the region covered by contigs AC125051 and AC131674.