What’s Bred in the Bone: Calcium Channels in Lymphocytes

Calcium (Ca 2+ ) is an important second messenger in lymphocytes and is essential in regulating various intracellular pathways that control critical cell functions. Ca 2+ channels are located in the plasma membrane and intracellular membranes, facilitating Ca 2+ entry into the cytoplasm. Upon Ag receptor stimulation, Ca 2+ can enter the lymphocyte via the Ca 2+ release-activated Ca 2+ channel found in the plasma membrane. The increase of cytosolic Ca 2+ modulates signaling pathways, resulting in the transcription of target genes implicated in differentiation, activation, proliferation, survival, and apoptosis of lymphocytes. Along with Ca 2+ release-activated Ca 2+ channels, several other channels have been found in the membranes of T and B lymphocytes contributing to key cellular events. Among them are the transient receptor potential channels, the P2X receptors, voltage-dependent Ca 2+ channels, and the inositol 1,4,5-trisphosphate receptor as well as the N -methyl-d-aspartate receptors. In this article, we review the contributions of these channels to mediating Ca 2+ currents that drive specific lymphocyte functions.