Figure 6.

Mitochondrial Midzone and Peripheral Fission. (A) Shows the fate of dividing mitochondria through the process of midzone mitochondrial fission (defined as fission occurring within the central 50% of a mitochondrion). Midzone fission occurs at sites guided by actin and PDZD8 mitochondrial–ER tethering, at areas of endoplasmic reticulum pre-constriction. Midzone fission is proposed to rely predominantly on MFF and Drp1 assembly. Midzone fission appears to support cell proliferation and mitochondrial biogenesis. (B) Shows the fate of dividing mitochondria through peripheral fission events (defined as fission occurring at the peripheral 0–25% of the mitochondrion). Peripheral fission is also mediated by Drp1; however, this process appears to rely on Fis1 and lysosomal contact to mediate Drp1 assembly. Division at the periphery enables damaged material to be shed into smaller mitochondria destined for mitophagy, an important mechanism for mitochondrial quality control.