The Discovery of Novel Experimental Therapies for Inflammatory Arthritis

Figure 2

The Role of Syk in Antigen-Mediated Activation of the B-cell Receptor. The B-cell receptor (BCR) is composed of a ligand binding moiety that interacts with antigen (Ag) and a signaling moiety in the form of the heterodimer, Ig-𝛼/Ig-𝛽 complex, (also known as CD79) which is held together by disulfide bridges. Each component of the Ig-𝛼/Ig-𝛽 heterodimer complex spans the plasma membrane and also possesses a cytoplasmic tail component containing the immunoreceptor tyrosine-based activation motif (ITAM). In this example, the binding of Ag to BCR triggers phosphorylation of Syk. Activation of Syk regulates phospholipase C𝛾 (PLC𝛾) activity. PLC𝛾2 was recently shown to be required for the formation, maintenance and survival of memory B cells within germinal centers [67].