Transmembrane signalling by the B-cell antigen receptor.

Crosslinking the B-cell antigen receptor is sufficient to generate intracellular signals. Recent work has shown that this signalling capability can be ascribed to the presence of the alpha and beta sheath proteins within the antigen receptor that couple it to signal transduction pathways. However, a variety of other transmembrane proteins, including CD19, CD21, CD22, CD32 and CD45, can also associate with the receptor and we are beginning to understand how they may act in concert with it to efficiently regulate B lymphocyte activity in response to antigen.