Regulation of Calcium Homeostasis by ER Redox: A Close-Up of the ER/Mitochondria Connection.

Calcium signaling plays an important role in cell survival by influencing mitochondria-related processes such as energy production and apoptosis. The endoplasmic reticulum (ER) is the main storage compartment for cell calcium (Ca2+ ; ~60-500μM), and the Ca2+ released by the ER has a prompt effect on the homeostasis of the juxtaposed mitochondria. Recent findings have highlighted a close connection between ER redox and Ca2+ signaling that is mediated by Ca2+ -handling proteins. This paper describes the redox-regulated mediators and mechanisms that orchestrate Ca2+ signals from the ER to mitochondria.