Ancillary protein that assembles as a beta subunit with a voltage-gated potassium channel complex of pore-forming alpha subunits. Modulates the gating kinetics and enhances stability of the channel complex. Assembled with KCNB1 modulates the gating characteristics of the delayed rectifier voltage-dependent potassium channel KCNB1. Assembled with KCNQ1/KVLQT1 is proposed to form the slowly activating delayed rectifier cardiac potassium (IKs) channel. The outward current reaches its steady state only after 50 seconds. Assembled with KCNH2/HERG may modulate the rapidly activating component of the delayed rectifying potassium current in heart (IKr).
Subcellular locations: Cell membrane, Apical cell membrane, Membrane raft
Colocalizes with KCNB1 at the plasma membrane (By similarity). Targets to the membrane raft when associated with KCNQ1 (By similarity).