Dynamin inhibition blocks phagosome fragmentation. (A and C) 40 min after phagocytosis of mRFP1–E. coli, RAW cells were treated with the dynamin inhibitors dyngo-4a, dynole 34-2, or vehicle (DMSO); fixed at the indicated time points; and immunostained for E.coli. E. coli fluorescence labeling is shown in rainbow scale. Red and blue are the highest and lowest intensity levels, respectively. Dashed lines indicate the boundary of the cells. Scale bars: 5 µm. (B and D) The total volume of PDVs per cell for the indicated treatments. Data are mean ± SEM of sample of 25 cells from 3 independent experiments. Treatments were compared statistically using a one-way ANOVA with Tukey’s post hoc test. Conditions with different letters (a–c) indicate statistically significant difference (P < 0.05). (E) Macrophages treated with dynole 34-2 or DMSO (vehicle) internalized Alexa Fluor 546–labeled transferrin for 10 min before fixation. White dashes indicate cell boundaries. Scale bars: 30 µm.