<p>Lysosomes are central degradative organelles essential for cellular homeostasis, yet the mechanisms that maintain their integrity and function under stress remain incompletely understood. Here we identify a previously unrecognized lysosomal renewal process, termed budding-type fission (B-fission), which restores lysosomal function during hypoxia–reoxygenation stress. During B-fission, damaged lysosomes generate membrane buds that undergo scission to form small, fully functional lysosomes, independently of autophagic lysosome reformation. Mechanistically, mitochondrial-derived vesicles (MDVs) deliver the fission adaptor MFF to lysosomes, where MFF recruits the dynamin-related GTPase DRP1 to drive membrane scission. MIRO2 promotes the formation of MFF<sup>+</sup> MDVs through direct interaction with MFF, while the lysosomal membrane protein ITM2C binds MIRO2 to tether and guide MFF<sup>+</sup> MDVs to lysosomes, enabling efficient MFF delivery and subsequent B-fission. Notably, AMPK activation by 991 or metformin promotes MFF-dependent lysosomal B-fission under normoxic conditions, whereas AMPK inhibition by dorsomorphin suppresses B-fission during hypoxia–reoxygenation. This stress-responsive ITM2C–MIRO2–MFF–DRP1 axis co-opts the mitochondrial division machinery to drive lysosomal fission from damaged lysosomes, thereby enabling the undamaged components to reorganize into daughter lysosomes and promote lysosomal renewal. Thus, our findings uncover a fundamental mode of lysosomal renewal and reveal an unexpected role for MDV-mediated mitochondria–lysosome communication in mediating lysosomal quality control during ischaemia–reperfusion and related stresses.</p>

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Mitochondrial-derived vesicles drive budding-type fission of damaged lysosomes

  • Yuanchun Luo,
  • Jianglong Yu,
  • Zhuofan Li,
  • Wanning Li,
  • Le Jiang,
  • Chen Huang,
  • Zhouyi Rong,
  • Long Lin,
  • Yueguang Rong,
  • Chaojun Yan,
  • Zhishui Chen,
  • Jingfeng Tang,
  • He He,
  • Anbing Shi,
  • Zhiyin Song

摘要

Lysosomes are central degradative organelles essential for cellular homeostasis, yet the mechanisms that maintain their integrity and function under stress remain incompletely understood. Here we identify a previously unrecognized lysosomal renewal process, termed budding-type fission (B-fission), which restores lysosomal function during hypoxia–reoxygenation stress. During B-fission, damaged lysosomes generate membrane buds that undergo scission to form small, fully functional lysosomes, independently of autophagic lysosome reformation. Mechanistically, mitochondrial-derived vesicles (MDVs) deliver the fission adaptor MFF to lysosomes, where MFF recruits the dynamin-related GTPase DRP1 to drive membrane scission. MIRO2 promotes the formation of MFF+ MDVs through direct interaction with MFF, while the lysosomal membrane protein ITM2C binds MIRO2 to tether and guide MFF+ MDVs to lysosomes, enabling efficient MFF delivery and subsequent B-fission. Notably, AMPK activation by 991 or metformin promotes MFF-dependent lysosomal B-fission under normoxic conditions, whereas AMPK inhibition by dorsomorphin suppresses B-fission during hypoxia–reoxygenation. This stress-responsive ITM2C–MIRO2–MFF–DRP1 axis co-opts the mitochondrial division machinery to drive lysosomal fission from damaged lysosomes, thereby enabling the undamaged components to reorganize into daughter lysosomes and promote lysosomal renewal. Thus, our findings uncover a fundamental mode of lysosomal renewal and reveal an unexpected role for MDV-mediated mitochondria–lysosome communication in mediating lysosomal quality control during ischaemia–reperfusion and related stresses.