Structural highlights
Disease
CD79A_HUMAN Autosomal agammaglobulinemia. The disease is caused by variants 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.
Function
CD79A_HUMAN 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.[1] [2]
Publication Abstract from PubMed
The B cell receptor (BCR) complex plays a critical role in B cell development and immune responses. The assembly mechanisms underlying the BCR complex remain unknown. We determined the cryo-electron microscopy (cryo-EM) structures of human IgG-BCR and IgM-BCR, which consist of membrane-bound immunoglobulin molecules (mIg) and Igalpha/beta subunits at a 1:1 stoichiometry. Assembly of both BCR complexes involves their extracellular domains, membrane-proximal connection peptides, and transmembrane (TM) helices. The TM helices of mIgG and mIgM share a conserved set of hydrophobic and polar interactions with Igalpha/beta TM helices. By contrast, the IgG-Cgamma3 and IgM-Cmu4 domains interact with extracellular Ig-like domains of Igalpha/beta through head-to-tail and side-by-side modes, respectively. This work reveals the structural basis for BCR assembly and provides insights into BCR triggering.
Cryo-EM structures of two human B cell receptor isotypes.,Ma X, Zhu Y, Dong D, Chen Y, Wang S, Yang D, Ma Z, Zhang A, Zhang F, Guo C, Huang Z Science. 2022 Aug 19;377(6608):880-885. doi: 10.1126/science.abo3828. Epub 2022 , Aug 18. PMID:35981028[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Luisiri P, Lee YJ, Eisfelder BJ, Clark MR. Cooperativity and segregation of function within the Ig-alpha/beta heterodimer of the B cell antigen receptor complex. J Biol Chem. 1996 Mar 1;271(9):5158-63. PMID:8617796
- ↑ Tseng J, Eisfelder BJ, Clark MR. B-cell antigen receptor-induced apoptosis requires both Ig alpha and Ig beta. Blood. 1997 Mar 1;89(5):1513-20. PMID:9057631
- ↑ Ma X, Zhu Y, Dong, Chen Y, Wang S, Yang D, Ma Z, Zhang A, Zhang F, Guo C, Huang Z. Cryo-EM structures of two human B cell receptor isotypes. Science. 2022 Aug 19;377(6608):880-885. doi: 10.1126/science.abo3828. Epub 2022, Aug 18. PMID:35981028 doi:http://dx.doi.org/10.1126/science.abo3828
