This entry represents the ATP-binding cassette sub-family C member 12 (ABCC12, also known as multidrug resistance-associated protein 9 MRP9) from animals. It belongs to the MRP (multidrug resistance protein) subfamily of the ATP-binding cassette (ABC) transporter family []and its substrate specificity is currently unknown. ABCC12 may play a role during the latter part of the male meiotic prophase, spermatid development or in sperm function, as full-length ABCC12 appears to be expressed only in testicular germ cells and sperm of mouse and boar [, ]. The ABC transporter family is a group of membrane proteins that use the hydrolysis of ATP to power the translocation of a wide variety of substrates across cellular membranes. ABC transporters minimally consist of two conserved regions: a highly conserved nucleotide-binding domain (NBD) and a less conserved transmembrane domain (TMD). Eukaryotic ABC proteins are usually organised either as full transporters (containing two NBDs and two TMDs), or as half transporters (containing one NBD and one TMD), that have to form homo- or heterodimers in order to constitute a functional protein [].
