ATP-dependent metalloprotease that catalyzes the degradation of folded and unfolded proteins with a suitable degron sequence in the mitochondrial intermembrane region (PubMed:24315374, PubMed:26923599, PubMed:27786171, PubMed:31695197, PubMed:33237841). Plays an important role in regulating mitochondrial morphology and function by cleaving OPA1 at position S2, giving rise to a form of OPA1 that promotes maintenance of normal mitochondrial structure and mitochondrial protein metabolism (PubMed:18076378, PubMed:26923599, PubMed:27495975, PubMed:33237841). Ensures cell proliferation, maintains normal cristae morphology and complex I respiration activity, promotes antiapoptotic activity and protects mitochondria from the accumulation of oxidatively damaged membrane proteins (PubMed:22262461). Required to control the accumulation of nonassembled respiratory chain subunits (NDUFB6, OX4 and ND1) (PubMed:22262461). Involved in the mitochondrial adaptation in response to various signals, such as stress or developmental cues, by mediating degradation of mitochondrial proteins to rewire the mitochondrial proteome (PubMed:31695197). Catalyzes degradation of mitochondrial proteins, such as translocases, lipid transfer proteins and metabolic enzymes in response to nutrient starvation in order to limit mitochondrial biogenesis: mechanistically, YME1L is activated by decreased phosphatidylethanolamine levels caused by LPIN1 activity in response to mTORC1 inhibition (PubMed:31695197). Acts as a regulator of adult neural stem cell self-renewal by promoting mitochondrial proteome rewiring, preserving neural stem and progenitor cells self-renewal (By similarity). Required for normal, constitutive degradation of PRELID1 (PubMed:27495975). Catalyzes the degradation of OMA1 in response to membrane depolarization (PubMed:26923599). Mediates degradation of TIMM17A downstream of the integrated stress response (ISR) (PubMed:24315374).