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 (By similarity). . This is the function of ENSG00000104848 (KCNA7, potassium voltage-gated channel subfamily A member 7).