B-cell receptor CD22 (B-lymphocyte cell adhesion molecule) (BL-CAM) (Sialic acid-binding Ig-like lectin 2) (Siglec-2) (T-cell surface antigen Leu-14) (CD antigen CD22)
1_MHLLG 6_ PWLLL 11_ LVLEY 16_ LAFSD 21_ SSKWV 26_ FEHPE 31_ TLYAW 36_ EGACV 41_ WIPCT 46_ YRALD 51_ GDLES 56_ FILFH 61_ NPEYN 66_ KNTSK 71_ FDGTR 76_ LYEST 81_ KDGKV 86_ PSEQK 91_ RVQFL 96_ GDKNK 101_ NCTLS 106_ IHPVH 111_ LNDSG 116_ QLGLR 121_ MESKT 126_ EKWME 131_ RIHLN 136_ VSERP 141_ FPPHI 146_ QLPPE 151_ IQESQ 156_ EVTLT 161_ CLLNF 166_ SCYGY 171_ PIQLQ 176_ WLLEG 181_ VPMRQ 186_ AAVTS 191_ TSLTI 196_ KSVFT 201_ RSELK 206_ FSPQW 211_ SHHGK 216_ IVTCQ 221_ LQDAD 226_ GKFLS 231_ NDTVQ 236_ LNVKH 241_ TPKLE 246_ IKVTP 251_ SDAIV 256_ REGDS 261_ VTMTC 266_ EVSSS 271_ NPEYT 276_ TVSWL 281_ KDGTS 286_ LKKQN 291_ TFTLN 296_ LREVT 301_ KDQSG 306_ KYCCQ 311_ VSNDV 316_ GPGRS 321_ EEVFL 326_ QVQYA 331_ PEPST 336_ VQILH 341_ SPAVE 346_ GSQVE 351_ FLCMS 356_ LANPL 361_ PTNYT 366_ WYHNG 371_ KEMQG 376_ RTEEK 381_ VHIPK 386_ ILPWH 391_ AGTYS 396_ CVAEN 401_ ILGTG 406_ QRGPG 411_ AELDV 416_ QYPPK 421_ KVTTV 426_ IQNPM 431_ PIREG 436_ DTVTL 441_ SCNYN 446_ SSNPS 451_ VTRYE 456_ WKPHG 461_ AWEEP 466_ SLGVL 471_ KIQNV 476_ GWDNT 481_ TIACA 486_ ACNSW 491_ CSWAS 496_ PVALN 501_ VQYAP 506_ RDVRV 511_ RKIKP 516_ LSEIH 521_ SGNSV 526_ SLQCD 531_ FSSSH 536_ PKEVQ 541_ FFWEK 546_ NGRLL 551_ GKESQ 556_ LNFDS 561_ ISPED 566_ AGSYS 571_ CWVNN 576_ SIGQT 581_ ASKAW 586_ TLEVL 591_ YAPRR 596_ LRVSM 601_ SPGDQ 606_ VMEGK 611_ SATLT 616_ CESDA 621_ NPPVS 626_ HYTWF 631_ DWNNQ 636_ SLPYH 641_ SQKLR 646_ LEPVK 651_ VQHSG 656_ AYWCQ 661_ GTNSV 666_ GKGRS 671_ PLSTL 676_ TVYYS 681_ PETIG 686_ RRVAV 691_ GLGSC 696_ LAILI 701_ LAICG 706_ LKLQR 711_ RWKRT 716_ QSQQG 721_ LQENS 726_ SGQSF 731_ FVRNK 736_ KVRRA 741_ PLSEG 746_ PHSLG 751_ CYNPM 756_ MEDGI 761_ SYTTL 766_ RFPEM 771_ NIPRT 776_ GDAES 781_ SEMQR 786_ PPPDC 791_ DDTVT 796_ YSALH 801_ KRQVG 806_ DYENV 811_ IPDFP 816_ EDEGI 821_ HYSEL 826_ IQFGV 831_ GERPQ 836_ AQENV 841_DYVIL
1: Most highly expressed siglec (sialic acid-binding immunoglobulin-like lectin) on B-cells that plays a role in various aspects of B-cell biology including differentiation, antigen presentation, and trafficking to bone marrow (PubMed:34330755, PubMed:8627166). Binds to alpha 2,6-linked sialic acid residues of surface molecules such as CD22 itself, CD45 and IgM in a cis configuration. Can also bind to ligands on other cells as an adhesion molecule in a trans configuration (PubMed:20172905). Acts as an inhibitory coreceptor on the surface of B-cells and inhibits B-cell receptor induced signaling, characterized by inhibition of the calcium mobilization and cellular activation. Mechanistically, the immunoreceptor tyrosine-based inhibitory motif domain is phosphorylated by the Src kinase LYN, which in turn leads to the recruitment of the protein tyrosine phosphatase 1/PTPN6, leading to the negative regulation of BCR signaling (PubMed:8627166). If this negative signaling from is of sufficient strength, apoptosis of the B-cell can be induced (PubMed:20516366)