Ca²+ signaling in B cells.

An increase in intracellular Ca²+ concentration is one of the major initial steps in B-cell activation that occurs within minutes after antigen receptor (BCR) engagement. In recent years, significant advances have been made in characterizing molecular mechanisms of Ca²+ signaling in lymphocytes, although the majority of work was done on T cells. This mini-review discusses several underexplored areas of Ca²+ signaling in B cells: (1) Ca²+ signaling in immune synapse and multifaceted Ca²+ responses within a single cell, (2) source of Ca²+ involved in Ca²+-dependent protein phosphorylation events and the role of store-operated influx, (3) role of BCR coreceptors in Ca²+ signaling, and (4) Ca²+ signaling and maintenance of B-cell tolerance and clinical significance of Ca²+ signaling alterations.