CD79a and CD79b heterodimers are the important signaling components of B cell receptor (BCR) complex which plays a crucial role in B cell development and antibody production. BCR complexes are composed of a ligand-binding receptor (membrane immunoglobulin; mIg), non-covalently associated with the signaling com-ponent, a disulfide-linked heterodimer of CD79a (Igα) and CD79b (Igβ). Both CD79 subunits consist of an Ig-like domain, a transmembrane (TM) region, and a longer cytoplasmic tail (CYT) containing an immune-receptor tyrosine-based activation motif (ITAM).