Mitochondrial potassium channel located in the mitochondrial inner membrane. Together with ABCB8/MITOSUR, forms a protein complex localized in the mitochondria that mediates ATP-dependent potassium currents across the inner membrane (that is, mitoK(ATP) channel). May contribute to the homeostatic control of cellular metabolism under stress conditions by regulating the mitochondrial matrix volume. Channel activity inhibited by ATP via ABCB8/MITOSUR subunit. The mitochondrial potassium channel (mitoK(ATP)) forms a heteromultimer.