Phagosomes undergo different modes of fragmentation. Macrophages engulfed mRFP1–E. coli for 1 h, were chased for 3 h to elicit fragmentation, and then were imaged live for 10-min intervals at a frequency of one frame every 3 s. (A and A′) Vesicle budding in phagosomes with intact E. coli rods (A, early budding) or after fragmentation (A′, late budding). (B and C) Tubulation events producing small phagosomal fragments or retracting into the phagosome (B) and constrictions forming large phagosomal fragments (C). Red arrows track single events described above. See corresponding Videos 5, 6, 7, and 8. Scale bars: 2 µm.