Macropinosomes are Key Players in Early Shigella Invasion and Vacuolar Escape in Epithelial Cells
Fig 5
Macropinosomes come into direct contact with the bacteria containing vacuole during vacuolar rupture.
Vacuolar rupture occurring during of WT and ΔipgD infections was studied using C-FIB/SET. Confocal microscopy was used to identify bacteria (cyan) within rupturing BCVs labeled by galectin-3-mOrange (red). (A) 3D ultrastructural data of WT reveals several macropinosomes (mp, orange) in direct contact (white arrow heads) with the BCV membrane (yellow), surrounding the bacteria (blue -cytosol, white- LPS). A dissociated BCV membrane is observed (A, white arrow) as well as smaller intraluminal vesicles within the macropinosome (A, black arrowhead). See also S8 Movie. (B) The ΔipgD strain exhibits less vesicles in contact with the BCV than the ΔipgD mutant strain, yet contact morphology is maintained (white arrow heads). Rupture on the opposing end to the contact point is observed (black arrow). See also S9 Movie. Overall 15 FIB/SET data sets of invasion sites were acquired (11 WT, 4 ΔipgD). For each strain, a representative data set of a site containing a rupturing BCV is presented.