ABCC2, also named as CMOAT, CMOAT1, CMRP and MRP2, is a member of the superfamily of ATP-binding cassette (ABC) transporters. ABC proteins transport various molecules across extra- and intra-cellular membranes. ABCC2 is a member of the MRP subfamily which is involved in multi-drug resistance. It is expressed in the canalicular (apical) part of the hepatocyte and functions in biliary transport. The substrates of ABCC2 include anticancer drugs such as vinblastine; therefore, it appears to contribute to drug resistance in mammalian cells. Several different mutations have been observed in patients with Dubin-Johnson syndrome (DJS), an autosomal recessive disorder characterized by conjugated hyperbilirubinemia.