What's Bred in the Bone: Calcium Channels in Lymphocytes.

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