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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, 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^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.