Double-edged alliance: mitochondrial surveillance by the UPS and autophagy

Mitochondria provide an essential role in the maintenance of cellular homeostasis with regard to energy generation, redox signaling, and programmed cell death. Consequently, fast adaptation to metabolic changes associated with developmental demands or stress induction requires a balanced coordination of mitochondrial biogenesis and removal of damaged mitochondria. Impaired mitochondrial maintenance is causally linked to many human pathologies and aging, including diabetes, cancer, and neurodegenerative diseases. Thus, it is of fundamental importance to understand cellular surveillance mechanisms that support a healthy mitochondrial network. In this review, we discuss the role of ubiquitin-dependent protein degradation in mitochondrial functionality.