Antigen presentation by B lymphocytes: how receptor signaling directs membrane trafficking.

Antigen capture and presentation onto MHC class II molecules by B lymphocytes is mediated by their surface antigen receptor - the B-cell receptor (BCR). The BCR must therefore coordinate the transport of MHC class II- and antigen-containing vesicles for them to converge and ensure efficient processing. Recently, progress has been made in understanding which and how these vesicular transport events are molecularly linked to BCR signaling. In particular, recent studies have emphasized the key roles of membrane microdomains and the actin cytoskeleton in regulation of membrane trafficking upon BCR engagement.