DNM1L (dynamin 1-like), also known as DRP1, is a dynamin-related GTPase that serves as the central executor of mitochondrial fission. It functions as a core component of the 'mitochondrial divisome,' a machinery conceptually analogous to bacterial cell division systems 1. DNM1L is recruited to mitochondrial division sites through adapter proteins including FIS1 and MFF, where it forms helical structures around mitochondria to mediate membrane scission 2. The protein regulates two mechanistically distinct fission pathways: peripheral fission mediated primarily by FIS1, which segregates damaged mitochondrial material for mitophagy, and midzone fission controlled by MFF and endoplasmic reticulum, which promotes mitochondrial biogenesis 3. DNM1L coordinates mitochondrial dynamics with quality control by partnering with FUNDC1 to couple fission with selective mitophagy, particularly under stress conditions 4. Additionally, DNM1L participates in mitochondrial-derived vesicle biogenesis, enabling selective quality control of multi-subunit protein complexes 5. Circadian regulation of DNM1L activity controls mitochondrial bioenergetics and ATP production 6. Dysregulation is implicated in neurodegenerative diseases and cancer; notably, DNM1L inhibition impairs glioma progression by disrupting mitochondrial respiratory cristae remodeling 7. Mutations cause encephalopathy from defective mitochondrial and peroxisomal fission.