ID:CD79A_HUMAN DESCRIPTION: RecName: Full=B-cell antigen receptor complex-associated protein alpha chain; AltName: Full=Ig-alpha; AltName: Full=MB-1 membrane glycoprotein; AltName: Full=Membrane-bound immunoglobulin-associated protein; AltName: Full=Surface IgM-associated protein; AltName: CD_antigen=CD79a; Flags: Precursor; 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. SUBUNIT: 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). 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. PTM: 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. PTM: Arginine methylation in the ITAM domain may interfere with the binding of SYK. It promotes signals leading to B cell differentiation (By similarity). DISEASE: Defects in CD79A are the cause of agammaglobulinemia type 3 (AGM3) [MIM:613501]. It is 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=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. SIMILARITY: Contains 1 Ig-like C2-type (immunoglobulin-like) domain. SIMILARITY: Contains 1 ITAM domain. WEB RESOURCE: Name=CD79Abase; Note=CD79A mutation db; URL="http://bioinf.uta.fi/CD79Abase/";
The RNAfold program from the Vienna RNA Package is used to perform the secondary structure predictions and folding calculations. The estimated folding energy is in kcal/mol. The more negative the energy, the more secondary structure the RNA is likely to have.
ModBase Predicted Comparative 3D Structure on P11912
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Orthologous Genes in Other Species
Orthologies between human, mouse, and rat are computed by taking the best BLASTP hit, and filtering out non-syntenic hits. For more distant species reciprocal-best BLASTP hits are used. Note that the absence of an ortholog in the table below may reflect incomplete annotations in the other species rather than a true absence of the orthologous gene.
KJ890873 - Synthetic construct Homo sapiens clone ccsbBroadEn_00267 CD79A gene, encodes complete protein. AK223371 - Homo sapiens mRNA for CD79A antigen isoform 1 precursor variant, clone: FCC103G02. M80462 - Human MB-1 mRNA, complete cds. M86921 - Human murine (MB1) gene, complete cds. AK315337 - Homo sapiens cDNA, FLJ96378, Homo sapiens CD79A antigen (immunoglobulin-associated alpha)(CD79A), transcript variant 1, mRNA. AF283770 - Homo sapiens clone TCBAP0759 mRNA sequence. BC113731 - Homo sapiens CD79a molecule, immunoglobulin-associated alpha, mRNA (cDNA clone MGC:142291 IMAGE:8322783), complete cds. BC113733 - Homo sapiens CD79a molecule, immunoglobulin-associated alpha, mRNA (cDNA clone MGC:142293 IMAGE:8322785), complete cds. JD320769 - Sequence 301793 from Patent EP1572962. S46706 - mb-1=membrane-bound immunoglobulin associated protein [human, Ly66 cells, mRNA, 1078 nt]. JD062346 - Sequence 43370 from Patent EP1572962. S79248 - Ig-alpha/mb-1=CD79a {alternatively spliced} [human, B cells, mRNA Partial, 564 nt]. HQ258131 - Synthetic construct Homo sapiens clone IMAGE:100072440 CD79a molecule, immunoglobulin-associated alpha (CD79A) gene, encodes complete protein. M74721 - Human B-cell antigen receptor (MB-1) mRNA, complete cds. X83540 - H.sapiens mb-1 mRNA for Ig-alpha, splice variant. S75217 - mb-1=IgM-alpha [human, mRNA, 1068 nt]. X13451 - Human mRNA for lymphocyte lineage-restricted mb-1 membrane glycoprotein C-term. (m-mb-1 homolog.). BC018964 - Homo sapiens cDNA clone IMAGE:3620560. JD255084 - Sequence 236108 from Patent EP1572962. JD389320 - Sequence 370344 from Patent EP1572962. JD151540 - Sequence 132564 from Patent EP1572962. JD498334 - Sequence 479358 from Patent EP1572962. JD409712 - Sequence 390736 from Patent EP1572962.
Biochemical and Signaling Pathways
BioCarta from NCI Cancer Genome Anatomy Project h_ctcfPathway - CTCF: First Multivalent Nuclear Factor h_bcrPathway - BCR Signaling Pathway h_bcrmolecule - B Cell Receptor Complex
Reactome (by CSHL, EBI, and GO)
Protein P11912 (Reactome details) participates in the following event(s):
R-HSA-983696 The Immunoglobulin of the BCR binds antigen R-HSA-983700 SYK binds the activated BCR R-HSA-5690740 CD22 binds B-cell receptor R-HSA-983703 p-6Y-SYK phosphorylates BLNK (SLP65) R-HSA-983707 SYK autophosphorylates at the activated BCR R-HSA-5690702 LYN phosphorylates CD22 R-HSA-5690701 SHP1 binds p-CD22 R-HSA-1112666 BLNK (SLP-65) Signalosome hydrolyzes phosphatidyinositol bisphosphate forming diacylglycerol and inositol-1,4,5-trisphosphate R-HSA-983695 Antigen activates B Cell Receptor (BCR) leading to generation of second messengers R-HSA-983705 Signaling by the B Cell Receptor (BCR) R-HSA-5690714 CD22 mediated BCR regulation R-HSA-1280218 Adaptive Immune System R-HSA-168256 Immune System
US Server
Sequence and Links to Tools and Databases 
Common Gene Haplotype Alleles 
