ABCB8 is a member of the superfamily of ATP-binding cassette (ABC) transporters. ABC proteins transport various molecules across extra- and intra-cellular membranes. ABC proteins are divided into seven distinct subfamilies (ABC1, MDR/TAP, MRP, ALD, OABP, GCN20, White). This protein is a member of the MDR/TAP subfamily. Members of the MDR/TAP subfamily are involved in multidrug resistance as well as antigen presentation. The function of this half-transporter has not yet been determined; however, it may involve the compartmentalization and transport of heme, as well as peptides, from the mitochondria to the nucleus and cytosol. The protein may also play a role in the transport of phospholipids into mitochondrial membranes.