Evolution of Mitochondria as Signaling Organelles

Mitochondria have primarily been viewed as bioenergetic and biosynthetic organelles that autonomously co-exist within the cell. However, the past two decades have provided evidence that mitochondria function as signaling organelles, constantly communicating with the cytosol to initiate biological events under homeo-static and stress conditions. Thus, the signaling function of the mitochondria may have been selected by nature from the inception of the early eukaryote, as discussed in this essay.