Required for the control of apoptosis during postnatal growth. Essential for proteolytic processing of an antiapoptotic form of OPA1 which prevents the release of mitochondrial cytochrome c in response to intrinsic apoptotic signals. Required for the maturation of PINK1 into its 52kDa mature form after its cleavage by mitochondrial-processing peptidase (MPP). Promotes cleavage of serine/threonine-protein phosphatase PGAM5 in damaged mitochondria in response to loss of mitochondrial membrane potential. Mediates differential cleavage of PINK1 and PGAM5 depending on the health status of mitochondria, disassociating from PINK1 and associating with PGAM5 in response to mitochondrial membrane potential loss. Required for processing of CLPB into a form with higher protein disaggregase activity by removing an autoinhibitory N-terminal peptide. Promotes processing of DIABLO/SMAC in the mitochondrion which is required for DIABLO apoptotic activity. Also required for cleavage of STARD7 and TTC19. Promotes changes in mitochondria morphology regulated by phosphorylation of P-beta domain