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P20273 (CD22_HUMAN) Reviewed, UniProtKB/Swiss-Prot

Last modified April 16, 2014. Version 160. Feed History...

Clusters with 100%, 90%, 50% identity | Documents (6) | Third-party data text xml rdf/xml gff fasta
to top of pageNames·Attributes·General annotation·Ontologies·Interactions·Alt products·Sequence annotation·Sequences·References·Web links·Cross-refs·Entry info·DocumentsCustomize order

Names and origin

Protein namesRecommended name:
B-cell receptor CD22
Alternative name(s):
B-lymphocyte cell adhesion molecule
Short name=BL-CAM
Sialic acid-binding Ig-like lectin 2
Short name=Siglec-2
T-cell surface antigen Leu-14
CD_antigen=CD22
Gene names
Name:CD22
Synonyms:SIGLEC2
OrganismHomo sapiens (Human) [Reference proteome]
Taxonomic identifier9606 [NCBI]
Taxonomic lineageEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresPrimatesHaplorrhiniCatarrhiniHominidaeHomo

Protein attributes

Sequence length847 AA.
Sequence statusComplete.
Sequence processingThe displayed sequence is further processed into a mature form.
Protein existenceEvidence at protein level

General annotation (Comments)

Function

Mediates B-cell B-cell interactions. May be involved in the localization of B-cells in lymphoid tissues. Binds sialylated glycoproteins; one of which is CD45. Preferentially binds to alpha-2,6-linked sialic acid. The sialic acid recognition site can be masked by cis interactions with sialic acids on the same cell surface. Upon ligand induced tyrosine phosphorylation in the immune response seems to be involved in regulation of B-cell antigen receptor signaling. Plays a role in positive regulation through interaction with Src family tyrosine kinases and may also act as an inhibitory receptor by recruiting cytoplasmic phosphatases via their SH2 domains that block signal transduction through dephosphorylation of signaling molecules.

Subunit structure

Predominantly monomer of isoform CD22-beta. Also found as heterodimer of isoform CD22-beta and a shorter isoform. Interacts with PTPN6/SHP-1, LYN, SYK, PIK3R1/PIK3R2 and PLCG1 upon phosphorylation. Interacts with GRB2, INPP5D and SHC1 upon phosphorylation By similarity. May form a complex with INPP5D/SHIP, GRB2 and SHC1. Ref.8 Ref.9 Ref.10

Subcellular location

Cell membrane; Single-pass type I membrane protein.

Tissue specificity

B-lymphocytes.

Domain

Contains 4 copies of a cytoplasmic motif that is referred to as the immunoreceptor tyrosine-based inhibitor motif (ITIM). This motif is involved in modulation of cellular responses. The phosphorylated ITIM motif can bind the SH2 domain of several SH2-containing phosphatases.

Post-translational modification

Phosphorylation of Tyr-762, Tyr-807 and Tyr-822 are involved in binding to SYK, GRB2 and SYK, respectively. Phosphorylation of Tyr-842 is involved in binding to SYK, PLCG2 and PIK3R1/PIK3R2.

Phosphorylated on tyrosine residues by LYN By similarity.

Sequence similarities

Belongs to the immunoglobulin superfamily. SIGLEC (sialic acid binding Ig-like lectin) family.

Contains 6 Ig-like C2-type (immunoglobulin-like) domains.

Contains 1 Ig-like V-type (immunoglobulin-like) domain.

Sequence caution

The sequence CAA36988.1 differs from that shown. Reason: Frameshift at position 806.

Alternative products

This entry describes 4 isoforms produced by alternative splicing. [Align] [Select]

Note: Additional isoforms seem to exist.
Isoform CD22-beta (identifier: P20273-1)

This isoform has been chosen as the 'canonical' sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry.
Isoform CD22-alpha (identifier: P20273-2)

The sequence of this isoform differs from the canonical sequence as follows:
     241-417: Missing.
Isoform 3 (identifier: P20273-3)

The sequence of this isoform differs from the canonical sequence as follows:
     330-417: Missing.
Note: No experimental confirmation available.
Isoform 4 (identifier: P20273-4)

The sequence of this isoform differs from the canonical sequence as follows:
     737-751: VRRAPLSEGPHSLGC → RCRVLRDAETSPGLR
     752-847: Missing.
Note: Gene prediction based on EST data.

Sequence annotation (Features)

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifier

Molecule processing

Signal peptide1 – 1919 Potential
Chain20 – 847828B-cell receptor CD22
PRO_0000014873

Regions

Topological domain20 – 687668Extracellular Potential
Transmembrane688 – 70619Helical; Potential
Topological domain707 – 847141Cytoplasmic Potential
Domain20 – 138119Ig-like V-type
Domain143 – 23593Ig-like C2-type 1
Domain242 – 32685Ig-like C2-type 2
Domain331 – 41686Ig-like C2-type 3
Domain419 – 50082Ig-like C2-type 4
Domain505 – 58278Ig-like C2-type 5
Domain593 – 67684Ig-like C2-type 6
Motif760 – 7656ITIM motif 1
Motif794 – 7996ITIM motif 2
Motif820 – 8256ITIM motif 3
Motif840 – 8456ITIM motif 4

Sites

Binding site1201Sialic acid By similarity

Amino acid modifications

Glycosylation671N-linked (GlcNAc...) Potential
Glycosylation1011N-linked (GlcNAc...) Potential
Glycosylation1121N-linked (GlcNAc...) Potential
Glycosylation1351N-linked (GlcNAc...) Potential
Glycosylation1641N-linked (GlcNAc...) Potential
Glycosylation2311N-linked (GlcNAc...) Potential
Glycosylation3631N-linked (GlcNAc...) Potential
Glycosylation4451N-linked (GlcNAc...) Potential
Glycosylation4481N-linked (GlcNAc...) Potential
Glycosylation4791N-linked (GlcNAc...) Potential
Glycosylation5741N-linked (GlcNAc...) Potential
Glycosylation6341N-linked (GlcNAc...) Potential
Disulfide bond39 ↔ 167 By similarity
Disulfide bond44 ↔ 102 By similarity
Disulfide bond161 ↔ 219 By similarity
Disulfide bond265 ↔ 309 By similarity
Disulfide bond353 ↔ 396 By similarity
Disulfide bond442 ↔ 484 By similarity
Disulfide bond529 ↔ 571 By similarity
Disulfide bond616 ↔ 659 By similarity

Natural variations

Alternative sequence241 – 417177Missing in isoform CD22-alpha.
VSP_002531
Alternative sequence330 – 41788Missing in isoform 3.
VSP_045363
Alternative sequence737 – 75115VRRAP…HSLGC → RCRVLRDAETSPGLR in isoform 4.
VSP_047223
Alternative sequence752 – 84796Missing in isoform 4.
VSP_047224
Natural variant341A → T. Ref.6
Corresponds to variant rs201453271 [ dbSNP | Ensembl ].
VAR_014133
Natural variant1521Q → E Observed with a marginally higher frequency in patients with systemic lupus erythematosus. Ref.6
VAR_003913
Natural variant2031E → K. Ref.6
VAR_014134
Natural variant5511G → R.
Corresponds to variant rs35715143 [ dbSNP | Ensembl ].
VAR_049903
Natural variant6391Y → H. Ref.2
Corresponds to variant rs1058407 [ dbSNP | Ensembl ].
VAR_014135
Natural variant6641S → G. Ref.6
Corresponds to variant rs17719289 [ dbSNP | Ensembl ].
VAR_003914
Natural variant6691R → C. Ref.6
VAR_003915
Natural variant7451G → D. Ref.6
Corresponds to variant rs10406069 [ dbSNP | Ensembl ].
VAR_003916

Experimental info

Sequence conflict4861A → R in CAA42006. Ref.1
Sequence conflict788 – 7892PD → RT in CAA42006. Ref.1

Sequences

Sequence LengthMass (Da)Tools
Isoform CD22-beta [UniParc].

Last modified July 15, 1999. Version 2.
Checksum: 38EB0BE4220ACA2D

FASTA84795,348
        10         20         30         40         50         60 
MHLLGPWLLL LVLEYLAFSD SSKWVFEHPE TLYAWEGACV WIPCTYRALD GDLESFILFH 

        70         80         90        100        110        120 
NPEYNKNTSK FDGTRLYEST KDGKVPSEQK RVQFLGDKNK NCTLSIHPVH LNDSGQLGLR 

       130        140        150        160        170        180 
MESKTEKWME RIHLNVSERP FPPHIQLPPE IQESQEVTLT CLLNFSCYGY PIQLQWLLEG 

       190        200        210        220        230        240 
VPMRQAAVTS TSLTIKSVFT RSELKFSPQW SHHGKIVTCQ LQDADGKFLS NDTVQLNVKH 

       250        260        270        280        290        300 
TPKLEIKVTP SDAIVREGDS VTMTCEVSSS NPEYTTVSWL KDGTSLKKQN TFTLNLREVT 

       310        320        330        340        350        360 
KDQSGKYCCQ VSNDVGPGRS EEVFLQVQYA PEPSTVQILH SPAVEGSQVE FLCMSLANPL 

       370        380        390        400        410        420 
PTNYTWYHNG KEMQGRTEEK VHIPKILPWH AGTYSCVAEN ILGTGQRGPG AELDVQYPPK 

       430        440        450        460        470        480 
KVTTVIQNPM PIREGDTVTL SCNYNSSNPS VTRYEWKPHG AWEEPSLGVL KIQNVGWDNT 

       490        500        510        520        530        540 
TIACAACNSW CSWASPVALN VQYAPRDVRV RKIKPLSEIH SGNSVSLQCD FSSSHPKEVQ 

       550        560        570        580        590        600 
FFWEKNGRLL GKESQLNFDS ISPEDAGSYS CWVNNSIGQT ASKAWTLEVL YAPRRLRVSM 

       610        620        630        640        650        660 
SPGDQVMEGK SATLTCESDA NPPVSHYTWF DWNNQSLPYH SQKLRLEPVK VQHSGAYWCQ 

       670        680        690        700        710        720 
GTNSVGKGRS PLSTLTVYYS PETIGRRVAV GLGSCLAILI LAICGLKLQR RWKRTQSQQG 

       730        740        750        760        770        780 
LQENSSGQSF FVRNKKVRRA PLSEGPHSLG CYNPMMEDGI SYTTLRFPEM NIPRTGDAES 

       790        800        810        820        830        840 
SEMQRPPPDC DDTVTYSALH KRQVGDYENV IPDFPEDEGI HYSELIQFGV GERPQAQENV 


DYVILKH 

« Hide

Isoform CD22-alpha [UniParc].

Checksum: 04F241A74FF61471
Show »

FASTA67075,799
Isoform 3 [UniParc].

Checksum: 18C7BFA0D4C94AE5
Show »

FASTA75985,675
Isoform 4 [UniParc].

Checksum: 1DA8314C562A6D00
Show »

FASTA75184,480

References

« Hide 'large scale' references
[1]"The B-cell antigen CD22 mediates monocyte and erythrocyte adhesion."
Stamenkovic I., Seed B.
Nature 345:74-77(1990) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM CD22-BETA).
[2]"cDNA cloning of the B cell membrane protein CD22: a mediator of B-B cell interactions."
Wilson G.L., Fox C.H., Fauci A.S., Kehrl J.H.
J. Exp. Med. 173:137-146(1991) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM CD22-BETA), VARIANT HIS-639.
Tissue: Tonsil.
[3]"Genomic structure and chromosomal mapping of the human CD22 gene."
Wilson G.L., Najfeld V., Kozlow E., Menniger J., Ward D., Kehrl J.H.
J. Immunol. 150:5013-5024(1993) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA] (ISOFORMS CD22-ALPHA AND CD22-BETA).
[4]Suzuki Y., Sugano S., Totoki Y., Toyoda A., Takeda T., Sakaki Y., Tanaka A., Yokoyama S.
Submitted (JUL-2006) to the EMBL/GenBank/DDBJ databases
Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA] (ISOFORM 3).
Tissue: Spleen.
[5]"The DNA sequence and biology of human chromosome 19."
Grimwood J., Gordon L.A., Olsen A.S., Terry A., Schmutz J., Lamerdin J.E., Hellsten U., Goodstein D., Couronne O., Tran-Gyamfi M., Aerts A., Altherr M., Ashworth L., Bajorek E., Black S., Branscomb E., Caenepeel S., Carrano A.V. expand/collapse author list , Caoile C., Chan Y.M., Christensen M., Cleland C.A., Copeland A., Dalin E., Dehal P., Denys M., Detter J.C., Escobar J., Flowers D., Fotopulos D., Garcia C., Georgescu A.M., Glavina T., Gomez M., Gonzales E., Groza M., Hammon N., Hawkins T., Haydu L., Ho I., Huang W., Israni S., Jett J., Kadner K., Kimball H., Kobayashi A., Larionov V., Leem S.-H., Lopez F., Lou Y., Lowry S., Malfatti S., Martinez D., McCready P.M., Medina C., Morgan J., Nelson K., Nolan M., Ovcharenko I., Pitluck S., Pollard M., Popkie A.P., Predki P., Quan G., Ramirez L., Rash S., Retterer J., Rodriguez A., Rogers S., Salamov A., Salazar A., She X., Smith D., Slezak T., Solovyev V., Thayer N., Tice H., Tsai M., Ustaszewska A., Vo N., Wagner M., Wheeler J., Wu K., Xie G., Yang J., Dubchak I., Furey T.S., DeJong P., Dickson M., Gordon D., Eichler E.E., Pennacchio L.A., Richardson P., Stubbs L., Rokhsar D.S., Myers R.M., Rubin E.M., Lucas S.M.
Nature 428:529-535(2004) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
[6]"Identification of the gene variations in human CD22."
Hatta Y., Tsuchiya N., Matsushita M., Shiota M., Hagiwara K., Tokunaga K.
Immunogenetics 49:280-286(1999) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 13-137; 139-239; 241-328 AND 418-502, VARIANTS THR-34; GLU-152; LYS-203; GLY-664; CYS-669 AND ASP-745.
[7]"Natural ligands of the B cell adhesion molecule CD22 beta carry N-linked oligosaccharides with alpha-2,6-linked sialic acids that are required for recognition."
Powell L.D., Sgroi D., Sjoberg E.R., Stamenkovic I., Varki A.
J. Biol. Chem. 268:7019-7027(1993) [PubMed] [Europe PMC] [Abstract]
Cited for: SIALIC ACID-BINDING.
[8]"A role in B cell activation for CD22 and the protein tyrosine phosphatase SHP."
Doody G.M., Justement L.B., Delibrias C.C., Matthews R.J., Lin J., Thomas M.L., Fearon D.T.
Science 269:242-244(1995) [PubMed] [Europe PMC] [Abstract]
Cited for: INTERACTION WITH PTPN6.
[9]"Involvement of p72syk kinase, p53/56lyn kinase and phosphatidyl inositol-3 kinase in signal transduction via the human B lymphocyte antigen CD22."
Tuscano J.M., Engel P., Tedder T.F., Agarwal A., Kehrl J.H.
Eur. J. Immunol. 26:1246-1252(1996) [PubMed] [Europe PMC] [Abstract]
Cited for: INTERACTION WITH LYN; SYK AND PIK3R1/PIK3R2.
[10]"CD22 associates with protein tyrosine phosphatase 1C, Syk, and phospholipase C-gamma(1) upon B cell activation."
Law C.L., Sidorenko S.P., Chandran K.A., Zhao Z., Shen S.H., Fischer E.H., Clark E.A.
J. Exp. Med. 183:547-560(1996) [PubMed] [Europe PMC] [Abstract]
Cited for: INTERACTION WITH PTPN6; SYK AND PLCG1.
[11]"CD22, a B lymphocyte-specific adhesion molecule that regulates antigen receptor signaling."
Tedder T.F., Tuscano J., Sato S., Kehrl J.H.
Annu. Rev. Immunol. 15:481-504(1997) [PubMed] [Europe PMC] [Abstract]
Cited for: REVIEW.
+Additional computationally mapped references.

Cross-references

Sequence databases

EMBL
GenBank
DDBJ
U62631 Genomic DNA. Translation: AAB06448.1.
U62631 Genomic DNA. Translation: AAB06449.1.
X59350 mRNA. Translation: CAA42006.1.
X52785 mRNA. Translation: CAA36988.1. Frameshift.
AK225625 mRNA. No translation available.
AC002132 Genomic DNA. No translation available.
AB012995 Genomic DNA. Translation: BAA36564.1.
AB012996 Genomic DNA. Translation: BAA36565.1.
AB012997 Genomic DNA. Translation: BAA36566.1.
AB012998 Genomic DNA. Translation: BAA36567.1.
AB012999 Genomic DNA. Translation: BAA36568.1.
AB013000 Genomic DNA. Translation: BAA36569.1.
AB013002 Genomic DNA. Translation: BAA36571.1.
AB013003 Genomic DNA. Translation: BAA36572.1.
AB013004 Genomic DNA. Translation: BAA36573.1.
AB013006 Genomic DNA. Translation: BAA36575.1.
PIRA35648.
RefSeqNP_001172028.1. NM_001185099.1.
NP_001172029.1. NM_001185100.1.
NP_001172030.1. NM_001185101.1.
NP_001762.2. NM_001771.3.
UniGeneHs.579691.

3D structure databases

ProteinModelPortalP20273.
SMRP20273. Positions 36-677.
ModBaseSearch...
MobiDBSearch...

Protein-protein interaction databases

BioGrid107371. 11 interactions.
IntActP20273. 7 interactions.
MINTMINT-3009156.

Chemistry

BindingDBP20273.
ChEMBLCHEMBL3218.
DrugBankDB00045. OspA lipoprotein.

Protein family/group databases

MEROPSI43.001.

PTM databases

PhosphoSiteP20273.

Polymorphism databases

DMDM6166019.

Proteomic databases

PaxDbP20273.
PRIDEP20273.

Protocols and materials databases

StructuralBiologyKnowledgebaseSearch...

Genome annotation databases

EnsemblENST00000085219; ENSP00000085219; ENSG00000012124. [P20273-1]
ENST00000341773; ENSP00000339349; ENSG00000012124. [P20273-2]
ENST00000536635; ENSP00000442279; ENSG00000012124. [P20273-3]
ENST00000544992; ENSP00000441237; ENSG00000012124. [P20273-4]
ENST00000594250; ENSP00000469984; ENSG00000012124. [P20273-2]
GeneID933.
KEGGhsa:933.
UCSCuc002nzb.4. human. [P20273-2]
uc010edt.3. human. [P20273-1]

Organism-specific databases

CTD933.
GeneCardsGC19P035826.
HGNCHGNC:1643. CD22.
HPACAB002418.
HPA024353.
MIM107266. gene.
neXtProtNX_P20273.
PharmGKBPA26201.
GenAtlasSearch...

Phylogenomic databases

eggNOGNOG287433.
HOVERGENHBG005272.
InParanoidP20273.
KOK06467.
OMAPTNYTWY.
OrthoDBEOG7VHSWK.
PhylomeDBP20273.
TreeFamTF334827.

Gene expression databases

ArrayExpressP20273.
BgeeP20273.
GenevestigatorP20273.

Family and domain databases

Gene3D2.60.40.10. 7 hits.
InterProIPR013162. CD80_C2-set.
IPR007110. Ig-like_dom.
IPR013783. Ig-like_fold.
IPR003599. Ig_sub.
IPR003598. Ig_sub2.
IPR013151. Immunoglobulin.
[Graphical view]
PfamPF08205. C2-set_2. 1 hit.
PF00047. ig. 2 hits.
[Graphical view]
SMARTSM00409. IG. 2 hits.
SM00408. IGc2. 4 hits.
[Graphical view]
PROSITEPS50835. IG_LIKE. 6 hits.
[Graphical view]
ProtoNetSearch...

Other

GeneWikiCD22.
GenomeRNAi933.
NextBio3874.
PROP20273.
SOURCESearch...

Entry information

Entry nameCD22_HUMAN
AccessionPrimary (citable) accession number: P20273
Secondary accession number(s): F5GYU4 expand/collapse secondary AC list , F5H7U3, O95699, O95701, O95702, O95703, Q01665, Q92872, Q92873, Q9UQA6, Q9UQA7, Q9UQA8, Q9UQA9, Q9UQB0, Q9Y2A6
Entry history
Integrated into UniProtKB/Swiss-Prot: February 1, 1991
Last sequence update: July 15, 1999
Last modified: April 16, 2014
This is version 160 of the entry and version 2 of the sequence. [Complete history]
Entry statusReviewed (UniProtKB/Swiss-Prot)
Annotation programChordata Protein Annotation Program
DisclaimerAny medical or genetic information present in this entry is provided for research, educational and informational purposes only. It is not in any way intended to be used as a substitute for professional medical advice, diagnosis, treatment or care.

Relevant documents

SIMILARITY comments

Index of protein domains and families

MIM cross-references

Online Mendelian Inheritance in Man (MIM) cross-references in UniProtKB/Swiss-Prot

Human polymorphisms and disease mutations

Index of human polymorphisms and disease mutations

Human entries with polymorphisms or disease mutations

List of human entries with polymorphisms or disease mutations

Human chromosome 19

Human chromosome 19: entries, gene names and cross-references to MIM

Human cell differentiation molecules

CD nomenclature of surface proteins of human leucocytes and list of entries