MIROs and DRP1 drive mitochondrial-derived vesicle biogenesis and promote quality control.

Mitochondrial-derived vesicles (MDVs) are implicated in diverse physiological processes-for example, mitochondrial quality control-and are linked to various neurodegenerative diseases. However, their specific cargo composition and complex molecular biogenesis are still unknown. Here we report the proteome and lipidome of steady-state TOMM20+ MDVs. We identified 107 high-confidence MDV cargoes, which include all β-barrel proteins and the TOM import complex. MDV cargoes are delivered as fully assembled complexes to lysosomes, thus representing a selective mitochondrial quality control mechanism for multi-subunit complexes, including the TOM machinery. Moreover, we define key biogenesis steps of phosphatidic acid-enriched MDVs starting with the MIRO1/2-dependent formation of thin membrane protrusions pulled along microtubule filaments, followed by MID49/MID51/MFF-dependent recruitment of the dynamin family GTPase DRP1 and finally DRP1-dependent scission. In summary, we define the function of MDVs in mitochondrial quality control and present a mechanistic model for global GTPase-driven MDV biogenesis.