Figure 1. A Schematic model of the mitochondrion’s life cycle and the roles of mitochondrial dynamics and autophagy in the segregation of dysfunctional mitochondria.

The mitochondrion cyclically shifts between a post fusion state (Network) and a post fission state (Solitary). Fusion is brief and triggers fission. Following a fission event, the daughter mitochondrion may either maintain intact membrane potential (red line), or depolarize (green line). If it depolarizes, it is unlikely to re-engage in further fusion events for the entire depolarization interval. In the case mitochondrial depolarization is transient and Δψ_m resumes, fusion capacity is restored (green to red short arrows). However, if Δψ_m depolarization is sustained, reduction in OPA1 follows and elimination by autophagy occurs.