Complement receptor type 2 (Cr2) (Complement C3d receptor) (Epstein-Barr virus receptor) (EBV receptor) (CD antigen CD21)
1_MGAAG 6_ LLGVF 11_ LALVA 16_ PGVLG 21_ ISCGS 26_ PPPIL 31_ NGRIS 36_ YYSTP 41_ IAVGT 46_ VIRYS 51_ CSGTF 56_ RLIGE 61_ KSLLC 66_ ITKDK 71_ VDGTW 76_ DKPAP 81_ KCEYF 86_ NKYSS 91_ CPEPI 96_ VPGGY 101_ KIRGS 106_ TPYRH 111_ GDSVT 116_ FACKT 121_ NFSMN 126_ GNKSV 131_ WCQAN 136_ NMWGP 141_ TRLPT 146_ CVSVF 151_ PLECP 156_ ALPMI 161_ HNGHH 166_ TSENV 171_ GSIAP 176_ GLSVT 181_ YSCES 186_ GYLLV 191_ GEKII 196_ NCLSS 201_ GKWSA 206_ VPPTC 211_ EEARC 216_ KSLGR 221_ FPNGK 226_ VKEPP 231_ ILRVG 236_ VTANF 241_ FCDEG 246_ YRLQG 251_ PPSSR 256_ CVIAG 261_ QGVAW 266_ TKMPV 271_ CEEIF 276_ CPSPP 281_ PILNG 286_ RHIGN 291_ SLANV 296_ SYGSI 301_ VTYTC 306_ DPDPE 311_ EGVNF 316_ ILIGE 321_ STLRC 326_ TVDSQ 331_ KTGTW 336_ SGPAP 341_ RCELS 346_ TSAVQ 351_ CPHPQ 356_ ILRGR 361_ MVSGQ 366_ KDRYT 371_ YNDTV 376_ IFACM 381_ FGFTL 386_ KGSKQ 391_ IRCNA 396_ QGTWE 401_ PSAPV 406_ CEKEC 411_ QAPPN 416_ ILNGQ 421_ KEDRH 426_ MVRFD 431_ PGTSI 436_ KYSCN 441_ PGYVL 446_ VGEES 451_ IQCTS 456_ EGVWT 461_ PPVPQ 466_ CKVAA 471_ CEATG 476_ RQLLT 481_ KPQHQ 486_ FVRPD 491_ VNSSC 496_ GEGYK 501_ LSGSV 506_ YQECQ 511_ GTIPW 516_ FMEIR 521_ LCKEI 526_ TCPPP 531_ PVIYN 536_ GAHTG 541_ SSLED 546_ FPYGT 551_ TVTYT 556_ CNPGP 561_ ERGVE 566_ FSLIG 571_ ESTIR 576_ CTSND 581_ QERGT 586_ WSGPA 591_ PLCKL 596_ SLLAV 601_ QCSHV 606_ HIANG 611_ YKISG 616_ KEAPY 621_ FYNDT 626_ VTFKC 631_ YSGFT 636_ LKGSS 641_ QIRCK 646_ ADNTW 651_ DPEIP 656_ VCEKE 661_ TCQHV 666_ RQSLQ 671_ ELPAG 676_ SRVEL 681_ VNTSC 686_ QDGYQ 691_ LTGHA 696_ YQMCQ 701_ DAENG 706_ IWFKK 711_ IPLCK 716_ VIHCH 721_ PPPVI 726_ VNGKH 731_ TGMMA 736_ ENFLY 741_ GNEVS 746_ YECDQ 751_ GFYLL 756_ GEKKL 761_ QCRSD 766_ SKGHG 771_ SWSGP 776_ SPQCL 781_ RSPPV 786_ TRCPN 791_ PEVKH 796_ GYKLN 801_ KTHSA 806_ YSHND 811_ IVYVD 816_ CNPGF 821_ IMNGS 826_ RVIRC 831_ HTDNT 836_ WVPGV 841_ PTCIK 846_ KAFIG 851_ CPPPP 856_ KTPNG 861_ NHTGG 866_ NIARF 871_ SPGMS 876_ ILYSC 881_ DQGYL 886_ LVGEA 891_ LLLCT 896_ HEGTW 901_ SQPAP 906_ HCKEV 911_ NCSSP 916_ ADMDG 921_ IQKGL 926_ EPRKM 931_ YQYGA 936_ VVTLE 941_ CEDGY 946_ MLEGS 951_ PQSQC 956_ QSDHQ 961_ WNPPL 966_ AVCRS 971_ RSLAP 976_ VLCGI 981_ AAGLI 986_ LLTFL 991_ IVITL 996_ YVISK 1001_ HRARN 1006_ YYTDT 1011_ SQKEA 1016_ FHLEA 1021_ REVYS 1026_VDPYN
1: Serves as a receptor for various ligands including complement component CD3d, HNRNPU OR IFNA1 (PubMed:1849076, PubMed:21527715, PubMed:7753047). When C3d is bound to antigens, attaches to C3d on B-cell surface and thereby facilitates the recognition and uptake of antigens by B-cells (PubMed:21527715). This interaction enhances B-cell activation and subsequent immune responses. Forms a complex with several partners on the surface of B-cells including CD19, FCRL5 and CD81, to form the B-cell coreceptor complex that plays a crucial role in B-cell activation and signaling (PubMed:1383329, PubMed:30107486). Also induces specific intracellular signaling separately from the BCR and CD19 by activating the tyrosine kinase SRC, which then phosphorylates nucleolin/NCL and triggers AKT and GSK3 kinase activities in a SYK/CD19-independent manner (PubMed:12938232). Acts as a ligand for CD23 (FcepsilonRII), a low-affinity receptor for IgE, which is expressed on B-cells and other immune cells, and thus participates in the regulation of IgE production (PubMed:1386409)
2: (Microbial infection) Acts as a receptor for Epstein-Barr virus