|Molecule Type||Antigen Expression||Molecular Weight|
Min / Max
|Lineage Restricted Molecule|
Type 1 glycoprotein
|37 / 37|
39 / 39
|CD79β is restricted on B lymphocytes, first appearing on the surface at the pre-B cell stage and remaining through all stages of B cell differentiation prior to plasma cells. Expression is upregulated in B-CLL and is present in early B cell maturation with marginal zone and follicular mantle B cells having stronger expression than germinal center. The surrogate l chain and a truncated Dm heavy chain are expressed on pre-B cells.|
|MOLECULAR FAMILY NAME: Belongs to the immunoglobulin supergene family.|
CD79β is a single-pass type-1 glycoprotein. It contains an 131 aa extracellular domain which contains a Ig-like V-type domain and 3 potential N-glycosylation sites, a 21 aa transmembrane domain and a 49 aa cytoplasmic domain which contains an ITIM motif. CD79β exists at the surface as a disulfide-linked heterodimer with CD79α non-covalently associated with membrane Ig. It is proposed that each BCR complex contains 2 heterodimers of CD79α and CD79β. All classes of heavy chains can associate with the CD79 heterodimer.
Alternative splicing yields 2 different isoforms. A truncated isoform of CD79β is only 125 aa and occurs in human B cells and B cell lines.
CD79β is phosphorylated on tyrosine upon B cell activation.
|LIGANDS AND MOLECULES ASSOCIATED WITH CD79β|
Membrane Ig binds to CD5, CD19,CD22,CD79α and CD79β. Different pairs of BCR-associated proteins (BAP) molecules have been identified which specifically associate with IgM or IgD. As with CD3/TCR phosphorylated ITAM motifs of CD79β bind to SH2 domains of B cell intracellular signaling molecules.
|CD79α and CD79β create a heterodimer that is disulfide linked and noncovalently binds to Ig to form BCR. The heterodimer is necessary to escort the receptor complex to the cell membrane. When mIgM binds binds antigen, the heterodimer transduces the signal and promotes endocytosis of bound antigen for intracellular degradation and presentation to T helper cells. Antigen binding leads to internalization and presentation of antigen to T cells via MHC molecules, or can signal the B cell directly, in the case of multivalent antigens which crosslink several mIg molecules. Crosslinking of BCR leads to the activation of B cells, development and differentiation.. This is dependent on CD79β for signal transduction. Transmembrane signaling through surface Ig leads to the rapid activation of a phospholipase C and tyrosine kinases. CD79β is phosphorylated on tyrosine as a result of B cell activation. The progression of pro-B cells to pre-B cells is blocked in CD79β deficient mice.|
BIOCHEMICAL ACTIVITY: No information.
DISEASE RELEVANCE AND FUNCTION OF CD79β IN INTACT ANIMAL: No information.
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD79β: No information.
SUBSTRATES: No information.
ENZYMES WHICH MODIFY CD79β: No information.
Database accession numbers
Revised June 25, 2008