Regulation of cellular calcium through signaling cross-talk involves an intricate interplay between the actions of receptors, G-proteins, and second messengers.

Various external stimuli regulate cellular Ca2+ fluxes. Information from these stimuli is transmitted to the cell interior by signal transducing systems that involve interactions between receptors, G-proteins, and enzymes that generate second messengers. The possible mechanisms by which "cross-talk" within and between these second messenger-generating systems provides an intricate molecular avenue for fine modulation of intracellular Ca2+ are reviewed.