Fig. 4.

Schematic representation of the different experimental conditions and the corresponding MSD and CSD analyses. Mitochondria within X. laevis melanocytes were analyzed under control conditions (CTRL) and after disrupting the cytoskeletal networks with different treatments: latrunculin-B (LAT) was used to disrupt F-actin; cells were transiently transfected with a dominant-negative vimentin mutant (mCherry-vim(1-138), ${\text{VIM}}^{-}$); microtubules were partially depolymerized with nocodazole (NOC). Mean Square Displacement (MSD) analysis was fitted with an anomalous diffusion model that features $\alpha$ and $D^{\ast }$. On average, CTRL (green line) and NOC (violet line) conditions displayed a diffusive behavior ($\alpha \sim 1$), while LAT (orange line) and ${\text{VIM}}^{-}$ (red line) showed superdiffusive ($\alpha >1$) and subdiffusive ($\alpha <1$) behaviors, respectively. Mitochondrial motility ($D^{\ast }$) increased in the absence of F-actin and was reduced in NOC and ${\text{VIM}}^{-}$ conditions. Green arrows indicate these tendencies. We detected the number of force events (blue arrows) acting on mitochondria through the Cumulative Square Displacement (CSD). The frequency of these events was higher in the absence of F-actin and lower when vimentin or microtubule networks were disrupted.