BIOCHEMISTRY OF ANTIGEN RECEPTOR SIGNALING IN MATURE AND DEVELOPING B-LYMPHOCYTES

The function of the surface antigen receptor of B cells (BCR) has been extensively studied with respect to the activation of mature B lympho cytes. B cells at other points of development (e.g., pre-B cells, imma ture B cells, and germinal center B cells) also er,press forms of the BCR, and for cells at these developmental timepoints, signaling throug h the BCR in some cases may lead ro outcomes other than B-cell activat ion. Understanding the molecular events that are initiated by BCR cros slinking would enhance our understanding of the regulation and functio nal results of BCR signaling throughout B-cell development. In this ar ticle we review the current understanding of BCR signal transduction f rom initiation of the signal through changes in expression of genes th at regulate the activation state. Costimulatory and modulatory molecul es are considered with regard to their ability to affect the sensitivi ty or outcome of the BCR signal. Finally, we discuss how BCR signal tr ansduction and the results of BCR signaling may differ at distinct sta ges in B-cell development.