The protein encoded by this gene is a member of the superfamily of ATP-binding cassette (ABC) transporters. ABC proteins transport various molecules across extra- and intra-cellular membranes. ABC genes are divided into seven distinct subfamilies (ABC1, MDR/TAP, MRP, ALD, OABP, GCN20, White). This protein is a member of the White subfamily. The human protein is involved in macrophage cholesterol efflux and may regulate cellular lipid homeostasis in other cell types. [provided by RefSeq, Jul 2008]