ATP-binding cassette sub-family B member 9 (ABCB9)

ATP-binding cassette sub-family B member 9 (ABCB9) is a membrane-associated transporter protein in the ATP-binding cassette (ABC) superfamily, specifically in the MDR/TAP subfamily. ABCB9 forms a homodimer and localizes primarily to the lysosomal membrane, where it mediates ATP-dependent transport of a broad range of cytosolic oligopeptides (from 6 to at least 59 amino acids, with some sequence preference) into the lysosomal lumen. Distinct from classical TAP transporters that operate in the endoplasmic reticulum for antigen presentation, ABCB9 (also called TAPL) functions mainly in peptide handling within lysosomes and is stabilized by interactions with lysosome-associated membrane proteins such as LAMP-1 and LAMP-2. Altered ABCB9 expression has been linked to cancer prognosis, and distinct isoforms may exist with different peptide substrate specificities[1][2][3][5].

Other names

ABC-type oligopeptide transporter ABCB9KIAA1520ABC transporter 9 proteinhABCB9TAPLEST122234ATP-binding cassette transporter 9TAP-like proteinATP-binding cassette, sub-family B (MDR/TAP), member 9

ATP-dependent translocation of cytosolic peptides into the lysosomal lumen for degradation