Mitophagy: Sensors, Regulators, and Effectors

Mitochondria are essential organelles involved in energy production, cell signaling, and cell fate. They represent a node for numerous signaling pathways involved both in the processes of cell survival and cell death. Thus, aged and/or dysfunctional mitochondria need to be selectively removed to protect the cells from excessive oxidative stress and cell death. Moreover, the biogenesis of new mitochondria should be compensated by the elimination of the oldest ones. Thus a mitochondrial quality control system is needed for achieving such a task. The selective degradation of mitochondria by autophagy (mitophagy) is a process whereby damaged mitochondria are sequestered into double-membrane vesicles called autophagosomes and transported to lysosomes for degradation. In physiological conditions mitophagy contributes to the maturation of different cellular subsets like red blood cells, the cardiomyocytes adaptation to hypoxia as well as to the selective transmission of the maternal mitochondrial genome (mitochondrial inheritance). Alteration of mitophagy is also associated to pathological situations such as Parkinson’s and Alzheimer’s diseases. Indeed, mutations in the key constituents of the mitophagy’s core machinery have been associated with these neurodegenerative diseases. Hence, understanding the mechanisms of mitophagy regulation and signaling not only would bring a new vision for the comprehension of the physiological adaptation in multicellular organisms but also might help in the development of effective clinical strategies against neurodegenerative diseases. This chapter aims to underline the current advances in the study of mitophagy in physiological and pathological situations.