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.
Subcellular locations: Membrane
Detected in kidney, in proximal tubules, glomerular endothelium, in vascular endothelium and in smooth muscle cells.