Identification of Miro as a mitochondrial receptor for myosin XIX

Abstract

Mitochondrial distribution in cells is critical for cellular function and proper inheritance during cell division. In mammalian cells, mitochondria are transported predominantly along microtubules by kinesin and dynein and along actin filaments by myosin. Myosin XIX (Myo19) associates with the outer mitochondrial membrane, but no specific receptor has been identified. Using proximity BioID labeling, we identified Miro-1 and Miro-2 as potential binding partners of Myo19. Interaction studies show that Miro-1 binds to a C-terminal fragment of the Myo19 tail region and that Miro recruits the Myo19 tail in vivo. This recruitment is regulated by the nucleotide-state of the N-terminal Rho-like GTPase domain of Miro. Notably, Myo19 protein stability in cells depends on its association with Miro. Finally, Myo19 regulates the subcellular distribution of mitochondria. Downregulation, as well as overexpression, of Myo19 induces perinuclear collapse of mitochondria, phenocopying the loss of kinesin KIF5 or its mitochondrial receptor Miro. These results suggest that Miro coordinates microtubule- and actin-based mitochondrial movement.