ID   CD22_PONPY              Reviewed;         330 AA.
AC   Q9N1E3;
DT   19-OCT-2002, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-2000, sequence version 1.
DT   03-AUG-2022, entry version 103.
DE   RecName: Full=B-cell receptor CD22 {ECO:0000250|UniProtKB:P20273};
DE   AltName: Full=Sialic acid-binding Ig-like lectin 2;
DE            Short=Siglec-2;
DE   AltName: CD_antigen=CD22;
DE   Flags: Precursor; Fragment;
GN   Name=CD22 {ECO:0000250|UniProtKB:P20273}; Synonyms=SIGLEC2;
OS   Pongo pygmaeus (Bornean orangutan).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia;
OC   Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae;
OC   Pongo.
OX   NCBI_TaxID=9600;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RX   PubMed=10722703; DOI=10.1074/jbc.275.12.8633;
RA   Brinkman-Van der Linden E.C.M., Sjoberg E.R., Juneja L.R., Crocker P.R.,
RA   Varki N., Varki A.;
RT   "Loss of N-glycolylneuraminic acid in human evolution: implications for
RT   sialic acid recognition by siglecs.";
RL   J. Biol. Chem. 275:8633-8640(2000).
CC   -!- FUNCTION: Mediates B-cell B-cell interactions. May be involved in the
CC       localization of B-cells in lymphoid tissues. Binds sialylated
CC       glycoproteins; one of which is CD45. Preferentially binds to alpha-2,6-
CC       linked sialic acid (By similarity). Upon ligand-induced tyrosine
CC       phosphorylation in the immune response seems to be involved in
CC       regulation of B-cell antigen receptor signaling. Plays a role in
CC       positive regulation through interaction with Src family tyrosine
CC       kinases and may also act as an inhibitory receptor by recruiting
CC       cytoplasmic phosphatases via their SH2 domains that block signal
CC       transduction through dephosphorylation of signaling cascade key
CC       molecules. {ECO:0000250}.
CC   -!- SUBUNIT: Interacts with PTPN6/SHP-1, LYN, SYK, PIK3R1/PIK3R2 and PLCG1
CC       upon phosphorylation. Interacts with GRB2, INPP5D and SHC1 upon
CC       phosphorylation (By similarity). May form a complex with INPP5D/SHIP,
CC       GRB2 and SHC1. {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Cell membrane; Single-pass type I membrane
CC       protein.
CC   -!- SIMILARITY: Belongs to the immunoglobulin superfamily. SIGLEC (sialic
CC       acid binding Ig-like lectin) family. {ECO:0000305}.
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DR   EMBL; AF199418; AAF44617.1; -; mRNA.
DR   AlphaFoldDB; Q9N1E3; -.
DR   SMR; Q9N1E3; -.
DR   GO; GO:0005886; C:plasma membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0030246; F:carbohydrate binding; IEA:UniProtKB-KW.
DR   GO; GO:0007155; P:cell adhesion; IEA:UniProtKB-KW.
DR   Gene3D; 2.60.40.10; -; 3.
DR   InterPro; IPR013162; CD80_C2-set.
DR   InterPro; IPR007110; Ig-like_dom.
DR   InterPro; IPR036179; Ig-like_dom_sf.
DR   InterPro; IPR013783; Ig-like_fold.
DR   InterPro; IPR003599; Ig_sub.
DR   InterPro; IPR003598; Ig_sub2.
DR   Pfam; PF08205; C2-set_2; 1.
DR   SMART; SM00409; IG; 3.
DR   SMART; SM00408; IGc2; 1.
DR   SUPFAM; SSF48726; SSF48726; 3.
DR   PROSITE; PS50835; IG_LIKE; 2.
PE   2: Evidence at transcript level;
KW   Cell adhesion; Cell membrane; Disulfide bond; Glycoprotein;
KW   Immunoglobulin domain; Isopeptide bond; Lectin; Membrane; Repeat; Signal.
FT   SIGNAL          1..17
FT                   /evidence="ECO:0000255"
FT   CHAIN           18..330
FT                   /note="B-cell receptor CD22"
FT                   /id="PRO_0000014877"
FT   TOPO_DOM        18..>330
FT                   /note="Extracellular"
FT                   /evidence="ECO:0000255"
FT   DOMAIN          18..136
FT                   /note="Ig-like V-type"
FT   DOMAIN          141..233
FT                   /note="Ig-like C2-type 1"
FT   DOMAIN          240..324
FT                   /note="Ig-like C2-type 2"
FT   BINDING         118
FT                   /ligand="N-acetylneuraminate"
FT                   /ligand_id="ChEBI:CHEBI:35418"
FT                   /evidence="ECO:0000250"
FT   CARBOHYD        65
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        99
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        110
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        133
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        162
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        187
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        229
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   DISULFID        37..165
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00114"
FT   DISULFID        42..100
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00114"
FT   DISULFID        159..217
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00114"
FT   DISULFID        263..307
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00114"
FT   NON_TER         330
SQ   SEQUENCE   330 AA;  37257 MW;  E7F67002FD5F5381 CRC64;
     MHLLGPWLLL LEYLAFSDSS KWAFEHPETL YAWEGACVWI PCTYRALDGA LESFILFHNP
     EYNKNTSKFD GTRLYESTKD GEVPSEQKRV QFLGDKSKNC TLSIHPVHVN DSGQLGLRME
     SKTEKWMERI HLNVSERPFP PHIQLPPEIQ ESQEVTLTCL LNFSCYGYPI QLQWFLEGVP
     VGQAAVNSTS LATKSVFTRS ELKFSPQWSH HGKIVTCQLH GADGKFLSND TVQLNVKHTP
     KLKIEVNPSD AIVREGDSVT MTCEVSSSNP KYTTVSWLKD GTPLKKQNAL MLTLQEVTKD
     QSGKYCCQVS NDVGPGRSEE VFLQVQYAPE