Determinants and functions of mitochondrial behavior.

Mitochondria are ancient organelles evolved from bacteria. Over the course of evolution, the behavior of mitochondria inside eukaryotic cells has changed dramatically, and the corresponding machineries that control it are in most cases new inventions. The evolution of mitochondrial behavior reflects the necessity to create a dynamic compartment to integrate the myriad mitochondrial functions with the status of other endomembrane compartments, such as the endoplasmic reticulum, and with signaling pathways that monitor cellular homeostasis and respond to stress. Here we review what has been discovered about the molecular machineries that work together to control the collective behavior of mitochondria in cells, as well as their physiological roles in healthy and disease states.