The ATP-binding cassette (ABC) transporter family are primary active transporters that use ATP hydrolysis to drive the transport of substrates across the membrane. The ABCB half transporter subfamily must dimerize to form a functional transporter. The ABC transporters of the mitochondrion (ATM) subfamily possess a mitochondrial-targeting signal peptide and are predicted to reside in the inner mitochondrial membrane. (Adapted from FBrf0224053 and FBrf0207211.)