ID CD79A_HUMAN Reviewed; 226 AA. AC P11912; A0N775; Q53FB8; DT 01-OCT-1989, integrated into UniProtKB/Swiss-Prot. DT 01-JUN-1994, sequence version 2. DT 01-MAY-2013, entry version 133. DE RecName: Full=B-cell antigen receptor complex-associated protein alpha chain; DE AltName: Full=Ig-alpha; DE AltName: Full=MB-1 membrane glycoprotein; DE AltName: Full=Membrane-bound immunoglobulin-associated protein; DE AltName: Full=Surface IgM-associated protein; DE AltName: CD_antigen=CD79a; DE Flags: Precursor; GN Name=CD79A; Synonyms=IGA, MB1; OS Homo sapiens (Human). OC Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; OC Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; OC Catarrhini; Hominidae; Homo. OX NCBI_TaxID=9606; RN [1] RP NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 1). RX PubMed=1395095; RA Leduc I., Preud'Homme J.L., Cogne M.; RT "Structure and expression of the mb-1 transcript in human lymphoid RT cells."; RL Clin. Exp. Immunol. 90:141-146(1992). RN [2] RP NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 1). RC TISSUE=Tonsil; RX PubMed=1534761; DOI=10.1002/eji.1830220641; RA Mueller B.S., Cooper L., Terhorst C.; RT "Cloning and sequencing of the cDNA encoding the human homologue of RT the murine immunoglobulin-associated protein B29."; RL Eur. J. Immunol. 22:1621-1625(1992). RN [3] RP NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 1). RX PubMed=1639443; DOI=10.1007/BF00215058; RA Flaswinkel H., Reth M.; RT "Molecular cloning of the Ig-alpha subunit of the human B-cell antigen RT receptor complex."; RL Immunogenetics 36:266-269(1992). RN [4] RP NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 1). RX PubMed=1729378; RA Yu L.M., Chang T.W.; RT "Human mb-1 gene: complete cDNA sequence and its expression in B cells RT bearing membrane Ig of various isotypes."; RL J. Immunol. 148:633-637(1992). RN [5] RP NUCLEOTIDE SEQUENCE [GENOMIC DNA / MRNA] (ISOFORM 1). RX PubMed=1538135; RA Ha H.J., Kubagawa H., Burrows P.D.; RT "Molecular cloning and expression pattern of a human gene homologous RT to the murine mb-1 gene."; RL J. Immunol. 148:1526-1531(1992). RN [6] RP NUCLEOTIDE SEQUENCE [GENOMIC DNA] (ISOFORM 1). RX PubMed=7916003; DOI=10.1007/BF00189974; RA Hashimoto S., Mohrenweiser H.W., Gregersen P.K., Chiorazzi N.; RT "Chromosomal localization, genomic structure, and allelic polymorphism RT of the human CD79 alpha (Ig-alpha/mb-1) gene."; RL Immunogenetics 40:287-295(1994). RN [7] RP NUCLEOTIDE SEQUENCE [GENOMIC DNA]. RX PubMed=8207205; RA Ha H., Barnoski B.L., Sun L., Emanuel B.S., Burrows P.D.; RT "Structure, chromosomal localization, and methylation pattern of the RT human mb-1 gene."; RL J. Immunol. 152:5749-5757(1994). RN [8] RP NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 2). RX PubMed=7643857; DOI=10.1016/0161-5890(95)00023-8; RA Hashimoto S., Chiorazzi N., Gregersen P.K.; RT "Alternative splicing of CD79a (Ig-alpha/mb-1) and CD79b (Ig-beta/B29) RT RNA transcripts in human B cells."; RL Mol. Immunol. 32:651-659(1995). RN [9] RP NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 2). RA Koyama M., Nakamura T.; RL Submitted (DEC-1994) to the EMBL/GenBank/DDBJ databases. RN [10] RP NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA] (ISOFORM 1). RC TISSUE=Small intestine; RA Totoki Y., Toyoda A., Takeda T., Sakaki Y., Tanaka A., Yokoyama S.; RL Submitted (APR-2005) to the EMBL/GenBank/DDBJ databases. RN [11] RP PROTEIN SEQUENCE OF 33-52. RX PubMed=7514267; DOI=10.1016/0161-5890(94)90061-2; RA Vasile S., Coligan J.E., Yoshida M., Seon B.K.; RT "Isolation and chemical characterization of the human B29 and mb-1 RT proteins of the B cell antigen receptor complex."; RL Mol. Immunol. 31:419-427(1994). RN [12] RP PRELIMINARY NUCLEOTIDE SEQUENCE [MRNA] OF 190-226 (ISOFORM 1). RX PubMed=2463161; RA Sakaguchi N., Kashiwamura S., Kimoto M., Thalmann P., Melchers F.; RT "B lymphocyte lineage-restricted expression of mb-1, a gene with CD3- RT like structural properties."; RL EMBO J. 7:3457-3464(1988). RN [13] RP FUNCTION. RX PubMed=8617796; DOI=10.1074/jbc.271.9.5158; RA Luisiri P., Lee Y.J., Eisfelder B.J., Clark M.R.; RT "Cooperativity and segregation of function within the Ig-alpha/beta RT heterodimer of the B cell antigen receptor complex."; RL J. Biol. Chem. 271:5158-5163(1996). RN [14] RP FUNCTION. RX PubMed=9057631; RA Tseng J., Eisfelder B.J., Clark M.R.; RT "B-cell antigen receptor-induced apoptosis requires both Ig alpha and RT Ig beta."; RL Blood 89:1513-1520(1997). RN [15] RP INVOLVEMENT IN AGM3. RX PubMed=10525050; DOI=10.1172/JCI7696; RA Minegishi Y., Coustan-Smith E., Rapalus L., Ersoy F., Campana D., RA Conley M.E.; RT "Mutations in Igalpha (CD79a) result in a complete block in B-cell RT development."; RL J. Clin. Invest. 104:1115-1121(1999). RN [16] RP PHOSPHORYLATION, AND MUTAGENESIS OF SER-197; SER-203 AND THR-209. RX PubMed=10900006; DOI=10.1073/pnas.97.15.8451; RA Mueller R., Wienands J., Reth M.; RT "The serine and threonine residues in the Ig-alpha cytoplasmic tail RT negatively regulate immunoreceptor tyrosine-based activation motif- RT mediated signal transduction."; RL Proc. Natl. Acad. Sci. U.S.A. 97:8451-8454(2000). RN [17] RP INVOLVEMENT IN AGM3. RX PubMed=11920841; DOI=10.1002/ajmg.10296; RA Wang Y., Kanegane H., Sanal O., Tezcan I., Ersoy F., Futatani T., RA Miyawaki T.; RT "Novel Igalpha (CD79a) gene mutation in a Turkish patient with B cell- RT deficient agammaglobulinemia."; RL Am. J. Med. Genet. 108:333-336(2002). RN [18] RP STRUCTURE BY NMR OF 184-195, PHOSPHORYLATION, AND INTERACTION WITH RP LYN. RX PubMed=10748115; DOI=10.1074/jbc.M909044199; RA Gaul B.S., Harrison M.L., Geahlen R.L., Burton R.A., Post C.B.; RT "Substrate recognition by the Lyn protein-tyrosine kinase. NMR RT structure of the immunoreceptor tyrosine-based activation motif RT signaling region of the B cell antigen receptor."; RL J. Biol. Chem. 275:16174-16182(2000). CC -!- FUNCTION: Required in cooperation with CD79B for initiation of the CC signal transduction cascade activated by binding of antigen to the CC B-cell antigen receptor complex (BCR) which leads to CC internalization of the complex, trafficking to late endosomes and CC antigen presentation. Also required for BCR surface expression and CC for efficient differentiation of pro- and pre-B-cells. Stimulates CC SYK autophosphorylation and activation. Binds to BLNK, bringing CC BLNK into proximity with SYK and allowing SYK to phosphorylate CC BLNK. Also interacts with and increases activity of some Src- CC family tyrosine kinases. Represses BCR signaling during CC development of immature B-cells. CC -!- SUBUNIT: Heterodimer of alpha and beta chains; disulfide-linked. CC Part of the B-cell antigen receptor complex where the alpha/beta CC chain heterodimer is non-covalently associated with an antigen- CC specific membrane-bound surface immunoglobulin of two heavy chains CC and two light chains. Interacts through its phosphorylated ITAM CC domain with the SH2 domains of SYK which stimulates SYK CC autophosphorylation and activation. Also interacts, when CC phosphorylated on Tyr-210, with the SH2 domain of BLNK/SLP65, CC bringing BLNK into proximity with SYK and allowing SYK to CC phosphorylate BLNK which is necessary for trafficking of the BCR CC to late endosomes. Interacts with Src-family tyrosine kinases CC including FYN and LYN, increasing their activity (By similarity). CC -!- SUBCELLULAR LOCATION: Cell membrane; Single-pass type I membrane CC protein. Note=Following antigen binding, the BCR has been shown to CC translocate from detergent-soluble regions of the cell membrane to CC lipid rafts although signal transduction through the complex can CC also occur outside lipid rafts (By similarity). CC -!- ALTERNATIVE PRODUCTS: CC Event=Alternative splicing; Named isoforms=2; CC Name=1; Synonyms=Long; CC IsoId=P11912-1; Sequence=Displayed; CC Name=2; Synonyms=Short; CC IsoId=P11912-2; Sequence=VSP_002476; CC -!- TISSUE SPECIFICITY: B-cells. CC -!- PTM: Phosphorylated on tyrosine, serine and threonine residues CC upon B-cell activation. Phosphorylation of tyrosine residues by CC Src-family kinases is an early and essential feature of the BCR CC signaling cascade. The phosphorylated tyrosines serve as docking CC sites for SH2-domain containing kinases, leading to their CC activation which in turn leads to phosphorylation of downstream CC targets. Phosphorylated by LYN. Phosphorylation of serine and CC threonine residues may prevent subsequent tyrosine CC phosphorylation. CC -!- PTM: Arginine methylation in the ITAM domain may interfere with CC the binding of SYK. It promotes signals leading to B cell CC differentiation (By similarity). CC -!- DISEASE: Agammaglobulinemia 3 (AGM3) [MIM:613501]: A primary CC immunodeficiency characterized by profoundly low or absent serum CC antibodies and low or absent circulating B cells due to an early CC block of B-cell development. Affected individuals develop severe CC infections in the first years of life. Note=The disease is caused CC by mutations affecting the gene represented in this entry. Two CC different mutations, one at the splice donor site of intron 2 and CC the other at the splice acceptor site for exon 3, have been CC identified. Both mutations give rise to a truncated protein. CC -!- SIMILARITY: Contains 1 Ig-like C2-type (immunoglobulin-like) CC domain. CC -!- SIMILARITY: Contains 1 ITAM domain. CC -!- WEB RESOURCE: Name=CD79Abase; Note=CD79A mutation db; CC URL="http://bioinf.uta.fi/CD79Abase/"; CC ----------------------------------------------------------------------- CC Copyrighted by the UniProt Consortium, see http://www.uniprot.org/terms CC Distributed under the Creative Commons Attribution-NoDerivs License CC ----------------------------------------------------------------------- DR EMBL; S46706; AAB23558.1; -; mRNA. DR EMBL; M80462; AAA59556.1; -; mRNA. DR EMBL; M74721; AAA60270.1; -; mRNA. DR EMBL; S75217; AAB20812.1; -; mRNA. DR EMBL; M86921; AAA59557.1; -; mRNA. DR EMBL; U05259; AAA20495.1; -; Genomic_DNA. DR EMBL; S79248; AAC60653.1; -; mRNA. DR EMBL; X83540; CAA58523.1; -; mRNA. DR EMBL; AK223371; BAD97091.1; -; mRNA. DR EMBL; X13451; CAA31802.1; ALT_SEQ; mRNA. DR IPI; IPI00008473; -. DR IPI; IPI00218322; -. DR PIR; I54539; A46477. DR PIR; S12504; S12504. DR RefSeq; NP_001774.1; NM_001783.3. DR RefSeq; NP_067612.1; NM_021601.3. DR UniGene; Hs.631567; -. DR PDB; 1CV9; NMR; -; A=184-195. DR PDBsum; 1CV9; -. DR DisProt; DP00502; -. DR ProteinModelPortal; P11912; -. DR MINT; MINT-6491159; -. DR STRING; 9606.ENSP00000221972; -. DR PhosphoSite; P11912; -. DR DMDM; 547896; -. DR PaxDb; P11912; -. DR PeptideAtlas; P11912; -. DR PRIDE; P11912; -. DR DNASU; 973; -. DR Ensembl; ENST00000221972; ENSP00000221972; ENSG00000105369. DR Ensembl; ENST00000444740; ENSP00000400605; ENSG00000105369. DR GeneID; 973; -. DR KEGG; hsa:973; -. DR UCSC; uc002orv.3; human. DR CTD; 973; -. DR GeneCards; GC19P042381; -. DR HGNC; HGNC:1698; CD79A. DR HPA; CAB000019; -. DR HPA; HPA017748; -. DR MIM; 112205; gene. DR MIM; 613501; phenotype. DR neXtProt; NX_P11912; -. DR Orphanet; 33110; Autosomal agammaglobulinemia. DR PharmGKB; PA26237; -. DR eggNOG; NOG41728; -. DR HOGENOM; HOG000074307; -. DR HOVERGEN; HBG050854; -. DR InParanoid; P11912; -. DR KO; K06506; -. DR OMA; PFLDMGE; -. DR OrthoDB; EOG4H464J; -. DR PhylomeDB; P11912; -. DR Pathway_Interaction_DB; bcr_5pathway; BCR signaling pathway. DR Reactome; REACT_6900; Immune System. DR EvolutionaryTrace; P11912; -. DR GenomeRNAi; 973; -. DR NextBio; 4076; -. DR Bgee; P11912; -. DR CleanEx; HS_CD79A; -. DR Genevestigator; P11912; -. DR GermOnline; ENSG00000105369; Homo sapiens. DR GO; GO:0019815; C:B cell receptor complex; ISS:UniProtKB. DR GO; GO:0009897; C:external side of plasma membrane; ISS:UniProtKB. DR GO; GO:0016021; C:integral to membrane; IEA:UniProtKB-KW. DR GO; GO:0045121; C:membrane raft; ISS:UniProtKB. DR GO; GO:0005771; C:multivesicular body; ISS:UniProtKB. DR GO; GO:0004888; F:transmembrane signaling receptor activity; IEA:InterPro. DR GO; GO:0030183; P:B cell differentiation; ISS:UniProtKB. DR GO; GO:0042100; P:B cell proliferation; ISS:UniProtKB. DR GO; GO:0050853; P:B cell receptor signaling pathway; ISS:UniProtKB. DR Gene3D; 2.60.40.10; -; 1. DR InterPro; IPR007110; Ig-like_dom. DR InterPro; IPR013783; Ig-like_fold. DR InterPro; IPR003598; Ig_sub2. DR InterPro; IPR013106; Ig_V-set. DR InterPro; IPR003110; Phos_immunorcpt_sig_ITAM. DR Pfam; PF02189; ITAM; 1. DR Pfam; PF07686; V-set; 1. DR SMART; SM00408; IGc2; 1. DR SMART; SM00077; ITAM; 1. DR PROSITE; PS50835; IG_LIKE; 1. DR PROSITE; PS51055; ITAM_1; 1. PE 1: Evidence at protein level; KW 3D-structure; Adaptive immunity; Alternative splicing; Cell membrane; KW Complete proteome; Direct protein sequencing; Disulfide bond; KW Glycoprotein; Immunity; Immunoglobulin domain; Membrane; Methylation; KW Phosphoprotein; Reference proteome; Signal; Transmembrane; KW Transmembrane helix. FT SIGNAL 1 32 FT CHAIN 33 226 B-cell antigen receptor complex- FT associated protein alpha chain. FT /FTId=PRO_0000014558. FT TOPO_DOM 33 143 Extracellular (Potential). FT TRANSMEM 144 165 Helical; (Potential). FT TOPO_DOM 166 226 Cytoplasmic (Potential). FT DOMAIN 33 116 Ig-like C2-type. FT DOMAIN 177 205 ITAM. FT SITE 210 210 Required for binding to BLNK (By FT similarity). FT MOD_RES 188 188 Phosphotyrosine; by SRC-type Tyr-kinases FT (By similarity). FT MOD_RES 199 199 Phosphotyrosine; by SRC-type Tyr-kinases FT (By similarity). FT MOD_RES 204 204 Asymmetric dimethylarginine; by PRMT1 (By FT similarity). FT MOD_RES 210 210 Phosphotyrosine; by Tyr-kinases (By FT similarity). FT CARBOHYD 57 57 N-linked (GlcNAc...) (Potential). FT CARBOHYD 63 63 N-linked (GlcNAc...) (Potential). FT CARBOHYD 73 73 N-linked (GlcNAc...) (Potential). FT CARBOHYD 88 88 N-linked (GlcNAc...) (Potential). FT CARBOHYD 97 97 N-linked (GlcNAc...) (Potential). FT CARBOHYD 112 112 N-linked (GlcNAc...) (Potential). FT DISULFID 54 106 Potential. FT DISULFID 119 119 Interchain (with C-136 in beta chain) FT (Potential). FT VAR_SEQ 89 127 GTLIIQNVNKSHGGIYVCRVQEGNESYQQSCGTYLRVRQ FT -> E (in isoform 2). FT /FTId=VSP_002476. FT MUTAGEN 197 197 S->A: Increased phosphorylation of Y-188; FT when associated with A-203 and V-209. FT MUTAGEN 203 203 S->A: Increased phosphorylation of Y-188; FT when associated with A-197 and V-209. FT MUTAGEN 209 209 T->V: Increased phosphorylation of Y-188; FT when associated with A-197 and A-203. FT CONFLICT 47 47 G -> V (in Ref. 10; BAD97091). FT CONFLICT 69 69 V -> I (in Ref. 3; AAA60270). FT CONFLICT 189 189 E -> G (in Ref. 10; BAD97091). SQ SEQUENCE 226 AA; 25038 MW; 6E5B837409969292 CRC64; MPGGPGVLQA LPATIFLLFL LSAVYLGPGC QALWMHKVPA SLMVSLGEDA HFQCPHNSSN NANVTWWRVL HGNYTWPPEF LGPGEDPNGT LIIQNVNKSH GGIYVCRVQE GNESYQQSCG TYLRVRQPPP RPFLDMGEGT KNRIITAEGI ILLFCAVVPG TLLLFRKRWQ NEKLGLDAGD EYEDENLYEG LNLDDCSMYE DISRGLQGTY QDVGSLNIGD VQLEKP //