Roles of mitophagy in cellular physiology and development

The autophagic degradation of mitochondria, or mitophagy, has been shown to occur in eukaryotic cells under various physiological conditions. Broadly, these fall into two categories: quality-control related mitophagy and developmentally induced mitophagy. Quality-control related mitophagy, which is the lysosomal/vacuolar degradation of malfunctioning or superfluous mitochondria, is an important housekeeping function in respiring eukaryotic cells. It plays an essential role in physiological homeostasis and its deregulation has been linked to the progression of late-onset diseases. On the other hand, developmental processes such as reticulocyte maturation have also been shown to involve mitophagy. Importantly, there are clear differences between these processes. Unlike our knowledge of the more general degradation of soluble cytosolic content during starvation-induced macroautophagy, the mechanisms involved in the selective autophagic degradation of mitochondria have only recently begun to receive significant attention. Here, we review the current literature on these topics and proceed to provide specific examples from yeast and mammalian systems. Finally, we cover experimental approaches, with a focus on proteomic methods dedicated to the study of mitophagy in different systems.