This protein mediates the 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. Homotetramer (Probable). Heterotetramer of potassium channel proteins (By similarity). The segment S4 is probably the voltage-sensor and is characterized by a series of positively charged amino acids at every third position. The tail may be important in modulation of channel activity and/or targeting of the channel to specific subcellular compartments. Phosphorylation of serine residues in the inactivation gate inhibits rapid channel closure. Could be a cloning artifact. Belongs to the potassium channel family. C (Shaw) (TC 1.A.1.2) subfamily. Kv3.4/KCNC4 sub-subfamily.