An ATP-sensitive potassium channel (or KATP channel) is a type of potassium channel that is gated by intracellular nucleotides ATP and ADP. ATP-sensitive potassium channels are composed of Kir6.x-type subunits and sulfonylurea receptor (SUR) subunits along with additional components. KATP channels are found in the plasma membrane; however some may also be found on subcellular membranes.