Potassium channel subunit that does not form functional channels by itself. Can form functional heterotetrameric channels with KCNB1 and KCNB2; modulates the delayed rectifier voltage-gated potassium channel activation and deactivation rates of KCNB1 and KCNB2 .
Subcellular locations: Cell membrane
May not reach the plasma membrane but remain in an intracellular compartment in the absence of KCNB1 or KCNB2 .
Detected in all tissues tested with the exception of skeletal muscle. Highly expressed in adult and fetal brain, fetal kidney and lung, and adult prostate and testis .