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P11912 (CD79A_HUMAN) Reviewed, UniProtKB/Swiss-Prot

Last modified April 16, 2014. Version 142. Feed History...

Clusters with 100%, 90%, 50% identity | Documents (5) | Third-party data text xml rdf/xml gff fasta
to top of pageNames·Attributes·General annotation·Ontologies·Alt products·Sequence annotation·Sequences·References·Web links·Cross-refs·Entry info·DocumentsCustomize order

Names and origin

Protein namesRecommended name:
B-cell antigen receptor complex-associated protein alpha chain
Alternative name(s):
Ig-alpha
MB-1 membrane glycoprotein
Membrane-bound immunoglobulin-associated protein
Surface IgM-associated protein
CD_antigen=CD79a
Gene names
Name:CD79A
Synonyms:IGA, MB1
OrganismHomo sapiens (Human) [Reference proteome]
Taxonomic identifier9606 [NCBI]
Taxonomic lineageEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresPrimatesHaplorrhiniCatarrhiniHominidaeHomo

Protein attributes

Sequence length226 AA.
Sequence statusComplete.
Sequence processingThe displayed sequence is further processed into a mature form.
Protein existenceEvidence at protein level

General annotation (Comments)

Function

Required in cooperation with CD79B for initiation of the signal transduction cascade activated by binding of antigen to the B-cell antigen receptor complex (BCR) which leads to internalization of the complex, trafficking to late endosomes and antigen presentation. Also required for BCR surface expression and for efficient differentiation of pro- and pre-B-cells. Stimulates SYK autophosphorylation and activation. Binds to BLNK, bringing BLNK into proximity with SYK and allowing SYK to phosphorylate BLNK. Also interacts with and increases activity of some Src-family tyrosine kinases. Represses BCR signaling during development of immature B-cells. Ref.13 Ref.14

Subunit structure

Heterodimer of alpha and beta chains; disulfide-linked. Part of the B-cell antigen receptor complex where the alpha/beta chain heterodimer is non-covalently associated with an antigen-specific membrane-bound surface immunoglobulin of two heavy chains and two light chains. Interacts through its phosphorylated ITAM domain with the SH2 domains of SYK which stimulates SYK autophosphorylation and activation. Also interacts, when phosphorylated on Tyr-210, with the SH2 domain of BLNK/SLP65, bringing BLNK into proximity with SYK and allowing SYK to phosphorylate BLNK which is necessary for trafficking of the BCR to late endosomes. Interacts with Src-family tyrosine kinases including FYN and LYN, increasing their activity By similarity. Ref.18

Subcellular location

Cell membrane; Single-pass type I membrane protein. Note: Following antigen binding, the BCR has been shown to translocate from detergent-soluble regions of the cell membrane to lipid rafts although signal transduction through the complex can also occur outside lipid rafts By similarity.

Tissue specificity

B-cells.

Post-translational modification

Phosphorylated on tyrosine, serine and threonine residues upon B-cell activation. Phosphorylation of tyrosine residues by Src-family kinases is an early and essential feature of the BCR signaling cascade. The phosphorylated tyrosines serve as docking sites for SH2-domain containing kinases, leading to their activation which in turn leads to phosphorylation of downstream targets. Phosphorylated by LYN. Phosphorylation of serine and threonine residues may prevent subsequent tyrosine phosphorylation. Ref.16 Ref.18

Arginine methylation in the ITAM domain may interfere with the binding of SYK. It promotes signals leading to B-cell differentiation By similarity.

Involvement in disease

Agammaglobulinemia 3, autosomal recessive (AGM3) [MIM:613501]: A primary immunodeficiency characterized by profoundly low or absent serum antibodies and low or absent circulating B-cells due to an early block of B-cell development. Affected individuals develop severe infections in the first years of life.
Note: The disease is caused by mutations affecting the gene represented in this entry. Two different mutations, one at the splice donor site of intron 2 and the other at the splice acceptor site for exon 3, have been identified. Both mutations give rise to a truncated protein. Ref.15 Ref.17

Sequence similarities

Contains 1 Ig-like C2-type (immunoglobulin-like) domain.

Contains 1 ITAM domain.

Alternative products

This entry describes 2 isoforms produced by alternative splicing. [Align] [Select]
Isoform 1 (identifier: P11912-1)

Also known as: Long;

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 2 (identifier: P11912-2)

Also known as: Short;

The sequence of this isoform differs from the canonical sequence as follows:
     89-127: GTLIIQNVNKSHGGIYVCRVQEGNESYQQSCGTYLRVRQ → E

Sequence annotation (Features)

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifier

Molecule processing

Signal peptide1 – 3232 Ref.11
Chain33 – 226194B-cell antigen receptor complex-associated protein alpha chain
PRO_0000014558

Regions

Topological domain33 – 143111Extracellular Potential
Transmembrane144 – 16522Helical; Potential
Topological domain166 – 22661Cytoplasmic Potential
Domain33 – 11684Ig-like C2-type
Domain177 – 20529ITAM

Sites

Site2101Required for binding to BLNK By similarity

Amino acid modifications

Modified residue1881Phosphotyrosine; by SRC-type Tyr-kinases By similarity
Modified residue1991Phosphotyrosine; by SRC-type Tyr-kinases By similarity
Modified residue2041Asymmetric dimethylarginine; by PRMT1 By similarity
Modified residue2101Phosphotyrosine; by Tyr-kinases By similarity
Glycosylation571N-linked (GlcNAc...) Potential
Glycosylation631N-linked (GlcNAc...) Potential
Glycosylation731N-linked (GlcNAc...) Potential
Glycosylation881N-linked (GlcNAc...) Potential
Glycosylation971N-linked (GlcNAc...) Potential
Glycosylation1121N-linked (GlcNAc...) Potential
Disulfide bond54 ↔ 106 Potential
Disulfide bond119Interchain (with C-136 in beta chain) Potential

Natural variations

Alternative sequence89 – 12739GTLII…LRVRQ → E in isoform 2.
VSP_002476

Experimental info

Mutagenesis1971S → A: Increased phosphorylation of Y-188; when associated with A-203 and V-209. Ref.16
Mutagenesis2031S → A: Increased phosphorylation of Y-188; when associated with A-197 and V-209. Ref.16
Mutagenesis2091T → V: Increased phosphorylation of Y-188; when associated with A-197 and A-203. Ref.16
Sequence conflict471G → V in BAD97091. Ref.10
Sequence conflict691V → I in AAA60270. Ref.3
Sequence conflict1891E → G in BAD97091. Ref.10

Sequences

Sequence LengthMass (Da)Tools
Isoform 1 (Long) [UniParc].

Last modified June 1, 1994. Version 2.
Checksum: 6E5B837409969292

FASTA22625,038
        10         20         30         40         50         60 
MPGGPGVLQA LPATIFLLFL LSAVYLGPGC QALWMHKVPA SLMVSLGEDA HFQCPHNSSN 

        70         80         90        100        110        120 
NANVTWWRVL HGNYTWPPEF LGPGEDPNGT LIIQNVNKSH GGIYVCRVQE GNESYQQSCG 

       130        140        150        160        170        180 
TYLRVRQPPP RPFLDMGEGT KNRIITAEGI ILLFCAVVPG TLLLFRKRWQ NEKLGLDAGD 

       190        200        210        220 
EYEDENLYEG LNLDDCSMYE DISRGLQGTY QDVGSLNIGD VQLEKP 

« Hide

Isoform 2 (Short) [UniParc].

Checksum: 176B170B710E6EEB
Show »

FASTA18820,786

References

« Hide 'large scale' references
[1]"Structure and expression of the mb-1 transcript in human lymphoid cells."
Leduc I., Preud'Homme J.L., Cogne M.
Clin. Exp. Immunol. 90:141-146(1992) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 1).
[2]"Cloning and sequencing of the cDNA encoding the human homologue of the murine immunoglobulin-associated protein B29."
Mueller B.S., Cooper L., Terhorst C.
Eur. J. Immunol. 22:1621-1625(1992) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 1).
Tissue: Tonsil.
[3]"Molecular cloning of the Ig-alpha subunit of the human B-cell antigen receptor complex."
Flaswinkel H., Reth M.
Immunogenetics 36:266-269(1992) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 1).
[4]"Human mb-1 gene: complete cDNA sequence and its expression in B cells bearing membrane Ig of various isotypes."
Yu L.M., Chang T.W.
J. Immunol. 148:633-637(1992) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 1).
[5]"Molecular cloning and expression pattern of a human gene homologous to the murine mb-1 gene."
Ha H.J., Kubagawa H., Burrows P.D.
J. Immunol. 148:1526-1531(1992) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA / MRNA] (ISOFORM 1).
[6]"Chromosomal localization, genomic structure, and allelic polymorphism of the human CD79 alpha (Ig-alpha/mb-1) gene."
Hashimoto S., Mohrenweiser H.W., Gregersen P.K., Chiorazzi N.
Immunogenetics 40:287-295(1994) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA] (ISOFORM 1).
[7]"Structure, chromosomal localization, and methylation pattern of the human mb-1 gene."
Ha H., Barnoski B.L., Sun L., Emanuel B.S., Burrows P.D.
J. Immunol. 152:5749-5757(1994) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].
[8]"Alternative splicing of CD79a (Ig-alpha/mb-1) and CD79b (Ig-beta/B29) RNA transcripts in human B cells."
Hashimoto S., Chiorazzi N., Gregersen P.K.
Mol. Immunol. 32:651-659(1995) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 2).
[9]Koyama M., Nakamura T.
Submitted (DEC-1994) to the EMBL/GenBank/DDBJ databases
Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 2).
[10]Totoki Y., Toyoda A., Takeda T., Sakaki Y., Tanaka A., Yokoyama S.
Submitted (APR-2005) to the EMBL/GenBank/DDBJ databases
Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA] (ISOFORM 1).
Tissue: Small intestine.
[11]"Isolation and chemical characterization of the human B29 and mb-1 proteins of the B cell antigen receptor complex."
Vasile S., Coligan J.E., Yoshida M., Seon B.K.
Mol. Immunol. 31:419-427(1994) [PubMed] [Europe PMC] [Abstract]
Cited for: PROTEIN SEQUENCE OF 33-52.
[12]"B lymphocyte lineage-restricted expression of mb-1, a gene with CD3-like structural properties."
Sakaguchi N., Kashiwamura S., Kimoto M., Thalmann P., Melchers F.
EMBO J. 7:3457-3464(1988) [PubMed] [Europe PMC] [Abstract]
Cited for: PRELIMINARY NUCLEOTIDE SEQUENCE [MRNA] OF 190-226 (ISOFORM 1).
[13]"Cooperativity and segregation of function within the Ig-alpha/beta heterodimer of the B cell antigen receptor complex."
Luisiri P., Lee Y.J., Eisfelder B.J., Clark M.R.
J. Biol. Chem. 271:5158-5163(1996) [PubMed] [Europe PMC] [Abstract]
Cited for: FUNCTION.
[14]"B-cell antigen receptor-induced apoptosis requires both Ig alpha and Ig beta."
Tseng J., Eisfelder B.J., Clark M.R.
Blood 89:1513-1520(1997) [PubMed] [Europe PMC] [Abstract]
Cited for: FUNCTION.
[15]"Mutations in Igalpha (CD79a) result in a complete block in B-cell development."
Minegishi Y., Coustan-Smith E., Rapalus L., Ersoy F., Campana D., Conley M.E.
J. Clin. Invest. 104:1115-1121(1999) [PubMed] [Europe PMC] [Abstract]
Cited for: INVOLVEMENT IN AGM3.
[16]"The serine and threonine residues in the Ig-alpha cytoplasmic tail negatively regulate immunoreceptor tyrosine-based activation motif-mediated signal transduction."
Mueller R., Wienands J., Reth M.
Proc. Natl. Acad. Sci. U.S.A. 97:8451-8454(2000) [PubMed] [Europe PMC] [Abstract]
Cited for: PHOSPHORYLATION, MUTAGENESIS OF SER-197; SER-203 AND THR-209.
[17]"Novel Igalpha (CD79a) gene mutation in a Turkish patient with B cell-deficient agammaglobulinemia."
Wang Y., Kanegane H., Sanal O., Tezcan I., Ersoy F., Futatani T., Miyawaki T.
Am. J. Med. Genet. 108:333-336(2002) [PubMed] [Europe PMC] [Abstract]
Cited for: INVOLVEMENT IN AGM3.
[18]"Substrate recognition by the Lyn protein-tyrosine kinase. NMR structure of the immunoreceptor tyrosine-based activation motif signaling region of the B cell antigen receptor."
Gaul B.S., Harrison M.L., Geahlen R.L., Burton R.A., Post C.B.
J. Biol. Chem. 275:16174-16182(2000) [PubMed] [Europe PMC] [Abstract]
Cited for: STRUCTURE BY NMR OF 184-195, PHOSPHORYLATION, INTERACTION WITH LYN.
+Additional computationally mapped references.

Web resources

CD79Abase

CD79A mutation db

Cross-references

Sequence databases

EMBL
GenBank
DDBJ
S46706 mRNA. Translation: AAB23558.1.
M80462 mRNA. Translation: AAA59556.1.
M74721 mRNA. Translation: AAA60270.1.
S75217 mRNA. Translation: AAB20812.1.
M86921 mRNA. Translation: AAA59557.1.
U05259 Genomic DNA. Translation: AAA20495.1.
S79248 mRNA. Translation: AAC60653.1.
X83540 mRNA. Translation: CAA58523.1.
AK223371 mRNA. Translation: BAD97091.1.
X13451 mRNA. Translation: CAA31802.1. Sequence problems.
PIRA46477. I54539.
S12504.
RefSeqNP_001774.1. NM_001783.3.
NP_067612.1. NM_021601.3.
UniGeneHs.631567.

3D structure databases

PDBe
RCSB PDB
PDBj
EntryMethodResolution (Å)ChainPositionsPDBsum
1CV9NMR-A184-195[»]
DisProtDP00502.
ProteinModelPortalP11912.
ModBaseSearch...
MobiDBSearch...

Protein-protein interaction databases

BioGrid107411. 11 interactions.
IntActP11912. 1 interaction.
MINTMINT-6491159.
STRING9606.ENSP00000221972.

PTM databases

PhosphoSiteP11912.

Polymorphism databases

DMDM547896.

Proteomic databases

PaxDbP11912.
PeptideAtlasP11912.
PRIDEP11912.

Protocols and materials databases

DNASU973.
StructuralBiologyKnowledgebaseSearch...

Genome annotation databases

EnsemblENST00000221972; ENSP00000221972; ENSG00000105369. [P11912-1]
ENST00000444740; ENSP00000400605; ENSG00000105369. [P11912-2]
ENST00000608019; ENSP00000477348; ENSG00000272985. [P11912-1]
ENST00000609866; ENSP00000476512; ENSG00000272985. [P11912-2]
GeneID973.
KEGGhsa:973.
UCSCuc002oru.3. human. [P11912-2]
uc002orv.3. human. [P11912-1]

Organism-specific databases

CTD973.
GeneCardsGC19P042381.
HGNCHGNC:1698. CD79A.
HPACAB000019.
HPA017748.
MIM112205. gene.
613501. phenotype.
neXtProtNX_P11912.
Orphanet33110. Autosomal agammaglobulinemia.
PharmGKBPA26237.
GenAtlasSearch...

Phylogenomic databases

eggNOGNOG41728.
HOGENOMHOG000074307.
HOVERGENHBG050854.
InParanoidP11912.
KOK06506.
OMAPFLDMGE.
OrthoDBEOG7J70GM.
PhylomeDBP11912.
TreeFamTF336032.

Enzyme and pathway databases

ReactomeREACT_6900. Immune System.
SignaLinkP11912.

Gene expression databases

ArrayExpressP11912.
BgeeP11912.
CleanExHS_CD79A.
GenevestigatorP11912.

Family and domain databases

Gene3D2.60.40.10. 1 hit.
InterProIPR007110. Ig-like_dom.
IPR013783. Ig-like_fold.
IPR003598. Ig_sub2.
IPR013106. Ig_V-set.
IPR003110. Phos_immunorcpt_sig_ITAM.
[Graphical view]
PfamPF02189. ITAM. 1 hit.
PF07686. V-set. 1 hit.
[Graphical view]
SMARTSM00408. IGc2. 1 hit.
SM00077. ITAM. 1 hit.
[Graphical view]
PROSITEPS50835. IG_LIKE. 1 hit.
PS51055. ITAM_1. 1 hit.
[Graphical view]
ProtoNetSearch...

Other

EvolutionaryTraceP11912.
GeneWikiCD79A.
GenomeRNAi973.
NextBio4076.
PROP11912.
SOURCESearch...

Entry information

Entry nameCD79A_HUMAN
AccessionPrimary (citable) accession number: P11912
Secondary accession number(s): A0N775, Q53FB8
Entry history
Integrated into UniProtKB/Swiss-Prot: October 1, 1989
Last sequence update: June 1, 1994
Last modified: April 16, 2014
This is version 142 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

PDB cross-references

Index of Protein Data Bank (PDB) cross-references

MIM cross-references

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

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