B Cell Receptor

The B cell receptor (BCR) is a complex, membrane-bound protein structure found on the surface of B lymphocytes (B cells). It plays a central role in the adaptive immune response by recognizing specific antigens, initiating signaling cascades that activate the B cell, and mediating antigen internalization for processing and presentation to helper T cells. The BCR is composed of membrane-bound immunoglobulin (mIg) and signal transduction subunits (CD79A/Igα and CD79B/Igβ). Upon antigen binding, ITAM motifs on CD79A/B are phosphorylated, triggering downstream signaling pathways involving Syk kinase, phospholipase C-γ2 (PLC-γ2), PI3K, Bruton’s tyrosine kinase (BTK), ultimately leading to changes in gene expression required for activation or differentiation. Aberrant activation or dysregulation of the BCR pathway contributes to hematologic malignancies, making it a therapeutic target.

Inhibition of downstream signaling pathways (e.g., BTK, PI3K, SYK) activated by BCR engagement.