Divalent cation signaling in immune cells.

Divalent cations of two alkaline earth metals Ca(2+) and Mg(2+) and the transition metal Zn(2+) play vital roles in the immune system, and several immune disorders are associated with disturbances of their function. Until recently only Ca(2+) was considered to serve as a second messenger. However, signaling roles for Mg(2+) and Zn(2+) have been recently described, leading to a reevaluation of their role as potential second messengers. We review here the roles of these cations as second messengers in light of recent advances in Ca(2+), Mg(2+), and Zn(2+) signaling in the immune system. Developing a better understanding of these signaling cations may lead to new therapeutic strategies for immune disorders.