Search Results

Overview

Uniprot ID	Q03519
Protein Name	Antigen peptide transporter 2
Gene Name	TAP2
Organism	Homo sapiens

Kla Sites from experimental identification

Position	Flanking peptide
356	EHEVCRYKEALEQCR

Function

ABC transporter associated with antigen processing. In complex with TAP1 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)

Protein Sequence

10 MRLPDLRPWT 20 SLLLVDAALL 30 WLLQGPLGTL 40 LPQGLPGLWL 50 EGTLRLGGLW 60 GLLKLRGLLG 70 FVGTLLLPLC 80 LATPLTVSLR 90 ALVAGASRAP 100 PARVASAPWS 110 WLLVGYGAAG 120 LSWSLWAVLS 130 PPGAQEKEQD 140 QVNNKVLMWR 150 LLKLSRPDLP 160 LLVAAFFFLV 170 LAVLGETLIP 180 HYSGRVIDIL 190 GGDFDPHAFA 200 SAIFFMCLFS 210 FGSSLSAGCR 220 GGCFTYTMSR 230 INLRIREQLF 240 SSLLRQDLGF 250 FQETKTGELN 260 SRLSSDTTLM 270 SNWLPLNANV 280 LLRSLVKVVG 290 LYGFMLSISP 300 RLTLLSLLHM 310 PFTIAAEKVY 320 NTRHQEVLRE 330 IQDAVARAGQ 340 VVREAVGGLQ 350 TVRSFGAEEH 360 EVCRYKEALE 370 QCRQLYWRRD 380 LERALYLLVR 390 RVLHLGVQML 400 MLSCGLQQMQ 410 DGELTQGSLL 420 SFMIYQESVG 430 SYVQTLVYIY 440 GDMLSNVGAA 450 EKVFSYMDRQ 460 PNLPSPGTLA 470 PTTLQGVVKF 480 QDVSFAYPNR 490 PDRPVLKGLT 500 FTLRPGEVTA 510 LVGPNGSGKS 520 TVAALLQNLY 530 QPTGGQVLLD 540 EKPISQYEHC 550 YLHSQVVSVG 560 QEPVLFSGSV 570 RNNIAYGLQS 580 CEDDKVMAAA 590 QAAHADDFIQ 600 EMEHGIYTDV 610 GEKGSQLAAG 620 QKQRLAIARA 630 LVRDPRVLIL 640 DEATSALDVQ 650 CEQALQDWNS 660 RGDRTVLVIA 670 HRLQTVQRAH 680 QILVLQEGKL QKLAQL

Gene Ontology

Classification	GO ID	Description
Cellular Component	GO:0005783	endoplasmic reticulum
Cellular Component	GO:0005789	endoplasmic reticulum membrane
Cellular Component	GO:0033116	endoplasmic reticulum-Golgi intermediate compartment membrane
Cellular Component	GO:0016020	membrane
Cellular Component	GO:0042824	MHC class I peptide loading complex
Cellular Component	GO:0030670	phagocytic vesicle membrane
Cellular Component	GO:0042825	TAP complex
Molecular Function	GO:0015433	ABC-type peptide antigen transporter activity
Molecular Function	GO:0015440	ABC-type peptide transporter activity
Molecular Function	GO:0005524	ATP binding
Molecular Function	GO:0016887	ATP hydrolysis activity
Molecular Function	GO:0046872	metal ion binding
Molecular Function	GO:0023029	MHC class Ib protein binding
Molecular Function	GO:0042605	peptide antigen binding
Molecular Function	GO:1904680	peptide transmembrane transporter activity
Molecular Function	GO:0046978	TAP1 binding
Molecular Function	GO:0046980	tapasin binding
Biological Process	GO:0002250	adaptive immune response
Biological Process	GO:0019885	antigen processing and presentation of endogenous peptide antigen via MHC class I
Biological Process	GO:0002489	antigen processing and presentation of endogenous peptide antigen via MHC class Ib via ER pathway, TAP-dependent
Biological Process	GO:0046967	cytosol to endoplasmic reticulum transport
Biological Process	GO:0006952	defense response
Biological Process	GO:0046968	peptide antigen transport
Biological Process	GO:0015833	peptide transport
Biological Process	GO:0015031	protein transport
Biological Process	GO:0055085	transmembrane transport

Reference

[1] Yang Z, Yan C, Ma J, Peng P, Ren X et al.. Lactylome analysis suggests lactylation-dependent mechanisms of metabolic adaptation in hepatocellular carcinoma.. Nat Metab 5(1):61-79. 2023 Jan. PMID: 36593272.

[2] Wu Q, Li Z, Gong T, Zheng X, Zhou X et al.. Porphyromonas gingivalis infection induces lysine lactylation reprogramming in human umbilical vein endothelial cells.. Front Cell Infect Microbiol 16:1706727. 2026. PMID: 41696360.