CD79A_HUMAN » B-cell antigen receptor complex-associated protein alpha chain

CD79A_HUMAN » B-cell antigen receptor complex-associated protein alpha chain
Magnify CD79A_HUMAN » B-cell antigen receptor complex-associated protein alpha chainEnlarged view of image
3D view in GLMol or JMol

gray dot

Download Coordinates

gray dot

Topology in Plasma membrane
Topologyextracellular side
cytoplasmic side
CD79A_HUMAN » B-cell antigen receptor complex-associated protein alpha chain » Ig-alpha;MB-1 membrane glycoprotein;Membrane-bound immunoglobulin-associated protein;Surface IgM-associated protein;
Hydrophobic Thickness 36.0 ± 2.8 Å
Tilt Angle 12 ± 9°
ΔGtransfer -21.9 kcal/mol
ΔGfold -11.6 kcal/mol
Links UniProtKB, Pfam, Interpro, iHOP, STRING, HGNC
Topology Out
TM Segments 142-167 (138-167)
Pathways

B cell receptor signaling pathway (KEGG)

Immune System (Reactome)

Primary immunodeficiency (KEGG)

PDB 1cv9 (184-195)
OPM none
Complexes none
Interactions

BTLA, Complex: CD79B:BTLA:CD79A:CD19

CD19, Complex: CD19:CD79A, PubMed

CD5, Complex: CD79A:CD5, PubMed

CD79B, Complex: CD79A:CD79B, PubMed

FATE1, Complex: FATE1:CD79A

FCAR, Complex: FCAR:CD79A, PubMed

IGHM, Complex: IGHM:CD79A, PubMed

PIGR, Complex: PIGR:CD79A, PubMed

PTPRC, Complex: PTPRC:CD79A:CD79B, PubMed

Domains

AA: 37-118, PDBID: 1OLZ, Subunit A, Seq Identity:26%, Immunoglobulin domain

AA: 185-204, PDBID: 1CV9, Subunit A, Seq Identity:100%, Immunoreceptor tyrosine-based activation motif

UniProt annotation for CD79A_HUMAN » B-cell antigen receptor complex-associated protein alpha chain
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).

TISSUE SPECIFICITY: B-cells.

DISEASE: Agammaglobulinemia 3, autosomal recessive (AGM3) OMIM: 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. 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.

UniProt features for CD79A_HUMAN » B-cell antigen receptor complex-associated protein alpha chain
SIGNAL 1 32
CHAIN 33 226 B-cell antigen receptor complex- associated protein alpha chain.
DOMAIN 33 116 Ig-like C2-type.
DOMAIN 177 205 ITAM.
SITE 210 210 Required for binding to BLNK (By similarity).
DISULFID 54 106 Potential.
DISULFID 119 119 Interchain (with C-136 in beta chain) (Potential).
Amino Acid Sequence for CD79A_HUMAN » B-cell antigen receptor complex-associated protein alpha chain
MPGGPGVLQA LPATIFLLFL LSAVYLGPGC QALWMHKVPA SLMVSLGEDA HFQCPHNSSN NANVTWWRVL HGNYTWPPEF LGPGEDPNGT LIIQNVNKSH GGIYVCRVQE GNESYQQSCG TYLRVRQPPP RPFLDMGEGT KNRIITAEGI ILLFCAVVPG TLLLFRKRWQ NEKLGLDAGD EYEDENLYEG LNLDDCSMYE DISRGLQGTY QDVGSLNIGD VQLEKP