B-cell receptor complex (IgG-type) (BCR)

The B-cell receptor (BCR) complex is a critical transmembrane protein assembly located on the surface of B cells, composed of a membrane-bound immunoglobulin (mIg) molecule and a signaling heterodimer (CD79A and CD79B). In memory B cells, the mIg component is often of the IgG isotype, which allows the cell to recognize and bind specific antigens with high affinity. Upon antigen binding, the BCR initiates complex intracellular signaling cascades, primarily through the activation of Bruton's tyrosine kinase (BTK) and PI3K, which are essential for B-cell survival, proliferation, and differentiation into plasma cells. In many B-cell malignancies, such as chronic lymphocytic leukemia and various lymphomas, the BCR signaling pathway is constitutively active, driving uncontrolled cell growth. Consequently, the BCR and its associated signaling components are major therapeutic targets; monoclonal antibodies are used to deplete BCR-positive cells, while small molecule inhibitors are employed to disrupt the survival signals transmitted by the receptor complex.

Other names

Cell-surface antigen specified by the IgG componentMembrane-bound immunoglobulin GmIgGB-cell antigen receptorSurface IgG

Monoclonal antibodies bind to components of the B-cell receptor complex or associated surface markers (like CD20) to induce cell lysis via ADCC or CDC; small molecule inhibitors target downstream signaling kinases like BTK to inhibit BCR-mediated survival signals.