The ATP-binding cassette (ABC) transporter family are primary active transporters that use ATP hydrolysis to drive the transport of substrates across the membrane. A functional transporter contains 12 transmembrane domains and 2 cytoplasmic nucleotide binding domains. The transporter may be encoded by one polypeptide (full transporters) or formed by a dimer of half transporters. (Adapted from FBrf0224053).