ATP binding cassette subfamily B member 8, mitochondrial (ABCB8)

ATP binding cassette subfamily B member 8 (ABCB8) is a mitochondrial inner membrane protein and an ATP-dependent transporter. It serves as the ATP-binding regulatory subunit in the mitochondrial ATP-sensitive potassium (mitoKATP) channel complex, in partnership with the pore-forming CCDC51 protein. ABCB8 regulates potassium ion flux in response to cellular ATP levels: when ATP is high, the channel closes and inhibits K+ uptake, while low ATP opens the channel, allowing K+ entry into the mitochondrial matrix. It also plays a key role in maintaining mitochondrial iron homeostasis and proper function of cytosolic iron-sulfur cluster enzymes, which are essential for normal cardiac physiology. Mutations or dysfunction in ABCB8 may result in disease phenotypes ranging from congenital malformation (acheiropody) to possible roles in cardiac ischemic injury or oxidative stress-responsive conditions. ABCB8, as a mitochondrial sulfonylurea-receptor, is a putative pharmacological target for drugs that modulate mitochondrial potassium channel activity, though no selective molecules are currently in clinical use.

Other names

Mitochondrial potassium channel ATP-binding subunitMitochondrial ATP-binding cassette 1Mitochondrial sulfonylurea-receptorM-ABC1MABC1MITOSURMitochondrial ABC protein

Diazoxide: opens mitochondrial ATP-sensitive potassium channels, promoting mitochondrial matrix K+ uptake, triggers mitochondrial swelling and protection against ischemia/reperfusion injury. Sulfonylureas: inhibit ATP-sensitive potassium channels by binding to sulfonylurea-receptor subunit (in plasma membrane and mitochondria).