Antigen peptide transporter 1 (APT1) (EC 7.4.2.-) (ATP-binding cassette sub-family B member 2) (Peptide supply factor 1) (Peptide transporter PSF1) (PSF-1) (Peptide transporter TAP1) (Peptide transporter involved in antigen processing 1) (Really interesting new gene 4 protein) (RING4)
1_MASSR 6_ CPAPR 11_ GCRCL 16_ PGASL 21_ AWLGT 26_ VLLLL 31_ ADWVL 36_ LRTAL 41_ PRIFS 46_ LLVPT 51_ ALPLL 56_ RVWAV 61_ GLSRW 66_ AVLWL 71_ GACGV 76_ LRATV 81_ GSKSE 86_ NAGAQ 91_ GWLAA 96_ LKPLA 101_ AALGL 106_ ALPGL 111_ ALFRE 116_ LISWG 121_ APGSA 126_ DSTRL 131_ LHWGS 136_ HPTAF 141_ VVSYA 146_ AALPA 151_ AALWH 156_ KLGSL 161_ WVPGG 166_ QGGSG 171_ NPVRR 176_ LLGCL 181_ GSETR 186_ RLSLF 191_ LVLVV 196_ LSSLG 201_ EMAIP 206_ FFTGR 211_ LTDWI 216_ LQDGS 221_ ADTFT 226_ RNLTL 231_ MSILT 236_ IASAV 241_ LEFVG 246_ DGIYN 251_ NTMGH 256_ VHSHL 261_ QGEVF 266_ GAVLR 271_ QETEF 276_ FQQNQ 281_ TGNIM 286_ SRVTE 291_ DTSTL 296_ SDSLS 301_ ENLSL 306_ FLWYL 311_ VRGLC 316_ LLGIM 321_ LWGSV 326_ SLTMV 331_ TLITL 336_ PLLFL 341_ LPKKV 346_ GKWYQ 351_ LLEVQ 356_ VRESL 361_ AKSSQ 366_ VAIEA 371_ LSAMP 376_ TVRSF 381_ ANEEG 386_ EAQKF 391_ REKLQ 396_ EIKTL 401_ NQKEA 406_ VAYAV 411_ NSWTT 416_ SISGM 421_ LLKVG 426_ ILYIG 431_ GQLVT 436_ SGAVS 441_ SGNLV 446_ TFVLY 451_ QMQFT 456_ QAVEV 461_ LLSIY 466_ PRVQK 471_ AVGSS 476_ EKIFE 481_ YLDRT 486_ PRCPP 491_ SGLLT 496_ PLHLE 501_ GLVQF 506_ QDVSF 511_ AYPNR 516_ PDVLV 521_ LQGLT 526_ FTLRP 531_ GEVTA 536_ LVGPN 541_ GSGKS 546_ TVAAL 551_ LQNLY 556_ QPTGG 561_ QLLLD 566_ GKPLP 571_ QYEHR 576_ YLHRQ 581_ VAAVG 586_ QEPQV 591_ FGRSL 596_ QENIA 601_ YGLTQ 606_ KPTME 611_ EITAA 616_ AVKSG 621_ AHSFI 626_ SGLPQ 631_ GYDTE 636_ VDEAG 641_ SQLSG 646_ GQRQA 651_ VALAR 656_ ALIRK 661_ PCVLI 666_ LDDAT 671_ SALDA 676_ NSQLQ 681_ VEQLL 686_ YESPE 691_ RYSRS 696_ VLLIT 701_ QHLSL 706_ VEQAD 711_ HILFL 716_ EGGAI 721_ REGGT 726_ HQQLM 731_ EKKGC 736_ YWAMV 741_QAPAD
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)