Mitochondria: the hub of cellular Ca2+ signaling.

Mitochondria couple cellular metabolic state with Ca(2+) transport processes. They therefore control not only their own intra-organelle [Ca(2+)], but they also influence the entire cellular network of cellular Ca(2+) signaling, including the endoplasmic reticulum, the plasma membrane, and the nucleus. Through the detailed study of mitochondrial roles in Ca(2+) signaling, a remarkable picture of inter-organelle communication has emerged. We here review the ways in which this system provides integrity and flexibility for the cell to cope with the countless demands throughout its life cycle and discuss briefly the mechanisms through which it can also drive cell death.