ABCB9

The membrane-associated 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 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, this protein may play a role in lysosomes. Alternative splicing of this gene results in distinct isoforms which are likely to have different substrate specifications. [provided by RefSeq]

Full Name

ATP-binding cassette, sub-family B (MDR/TAP), member 9

Function

ATP-dependent low-affinity peptide transporter which translocates a broad spectrum of peptides from the cytosol to the lysosomal lumen. Displays a broad peptide length specificity from 6-mer up to at least 59-mer peptides with an optimum of 23-mers. Favors positively charged, aromatic or hydrophobic residues in the N- and C-terminal positions whereas negatively charged residues as well as asparagine and methionine are not favored.

Biological Process

Antigen processing and presentation of endogenous peptide antigen via MHC class I
Peptide transport
Protein transport
Transmembrane transport

Cellular Location

Lysosome membrane. May be located in membrane rafts.