Part of Thermo Fisher Scientific




Antigen peptide transporter 1

See alternative names ATP-binding cassette sub-family B member 2,
Peptide supply factor 1,
Peptide transporter PSF1,
Peptide transporter TAP1,
Peptide transporter involved in antigen processing 1,
Really interesting new gene 4 protein

Uniprot Function Description

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:25656091, PubMed:25377891). 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:25377891, PubMed:25656091, PubMed:11274390). 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:7500034, PubMed:9256420, PubMed:11274390). As a component of the peptide loading complex (PLC), acts as a molecular scaffold essential for peptide-MHCI assembly and antigen presentation (PubMed:26611325, PubMed:1538751, PubMed:25377891).

Sample type

Human EDTA plasma and serum are the recommended sample types. Human citrate plasma and heparin plasma are also accepted. For other samples types e.g cerebrospinal fluid, (CSF), tissue or cell lysates please we recommend Olink Target 96 panels. Please note that protein expression levels are expected to vary in different sample types and certain assays may be affected by interfering substances such as hemolysate.


Precision (repeatability) is calculated from linearized NPX values over LOD.

Within run precision Coefficient of Variation (CV)
Between run precision Coefficient of Variation (CV)

Dilution factor

For optimal assay readout, Olink Explore is run using different dilutions of the original samples (undiluted, 1:10, 1:100 or 1:1000). The dilution factor for this assay is noted below and should be taken into account when estimating the appropriate addressable biological concentration of the protein based on the in vitro validation data.

Dilution factor

Sample distribution plot

The plot below shows the levels of protein measured in a number of commercial plasma samples. Healthy subjects are shown in blue and samples obtained from patients with a range of diseases are shown in red. The latter include inflammatory, cardiovascular, autoimmune & neurological diseases, as well as cancer. The data is shown to give a general idea of the sort of data range to expect, but cannot cover all potential levels that may be seen in clinical samples.

1614121086420−2NPXControl SamplesDisease Samples