TAP1

Chr 6p21.32

transporter 1, ATP binding cassette subfamily B member

Aliases:: PSF1, RING4, D6S114E
MANE:: ENST00000354258.5

OMIM: 170260 ↗NCBI: 6890 ↗Ensembl ↗

Annotations refreshed 9 hours ago.

Predicted protein structure

AlphaFold predicted structure

TAP1 · Q03518

v62025-08-01

Predicted Aligned Error matrix for TAP1 — diagonal shows residue index, colour shows pairwise prediction confidence (lower is better) — Predicted Aligned Error

Mean pLDDT

78.5/ 100

Confident

748 residues

Confidence breakdown

Very high(≥ 90)27%
Confident(70–90)48%
Low(50–70)16%
Very low(< 50)9%

Open interactive 3D viewer

AlphaFold (Jumper et al., 2021) · CC BY 4.0

Clinical relevance (Genomics England PanelApp)

Diagnostic Grade (Green)

COVID-19 research
BIALLELIC, autosomal or pseudoautosomal
Primary immunodeficiency or monogenic inflammatory bowel disease
BIALLELIC, autosomal or pseudoautosomal

Disease associations (Open Targets)

MHC class I deficiency
0.74
Immunodeficiency by defective expression of HLA class 1
0.66
MHC class II deficiency
0.37
autoimmune disorder of central nervous system
0.36
neurodegenerative disease
0.24
hereditary disease
0.19
neoplasm
0.11
cancer
0.11
melanoma
0.10
tuberculosis
0.10

Score is the Open Targets composite evidence score (0-1). Higher = stronger gene-disease association.

Protein function (UniProt)

Antigen peptide transporter 1

ABC transporter associated with antigen processing. In complex with TAP2 mediates unidirectional translocation of peptide antigens from cytosol to endoplasmic reticulum (ER) for loading onto MHC class I (MHCI) molecules (PubMed:25377891, PubMed:25656091). Uses the chemical energy of ATP to export peptides against the concentration gradient (PubMed:25377891). During the transport cycle alternates between 'inward-facing' state with peptide binding site facing the cytosol to 'outward-facing' state with peptide binding site facing the ER lumen. Peptide antigen binding to ATP-loaded TAP1-TAP2 induces a switch to hydrolysis-competent 'outward-facing' conformation ready for peptide loading onto nascent MHCI molecules. Subsequently ATP hydrolysis resets the transporter to the 'inward facing' state for a new cycle (PubMed:11274390, PubMed:25377891, PubMed:25656091). Typically transports intracellular peptide antigens of 8 to 13 amino acids that arise from cytosolic proteolysis via IFNG-induced immunoproteasome. Binds peptides with free N- and C-termini, the first three and the C-terminal residues being critical. Preferentially selects peptides having a highly hydrophobic residue at position 3 and hydrophobic or charged residues at the C-terminal anchor. Proline at position 2 has the most destabilizing effect (PubMed:11274390, PubMed:7500034, PubMed:9256420). As a component of the peptide loading complex (PLC), acts as a molecular scaffold essential for peptide-MHCI assembly and antigen presentation (PubMed:1538751, PubMed:25377891, PubMed:26611325)