Macropinosomes are Key Players in Early Shigella Invasion and Vacuolar Escape in Epithelial Cells
Fig 2
C-FIB/SET reveals the BCV is a tight compartment structurally distinct from surrounding vesicles.
(A) Confocal microscopy of an early stage invasion site, labeled for actin (magenta) and DNA (cyan). Actin enrichment is observed around a bacterium at the site of interest (Inset, green box). This site is correlated with the corresponding 3D FIB/SET data allowing ultrastructural visualization of the entire invasion site, presented in three orthogonal views. Surface membrane ruffling (gold) and inner cell structures are observed in detail. The same bacterium is identified (panel YZ, green) in division at the center of the volume. See also S1 Movie. (B) Typical structural components of the S. flexneri BCV. Bacterial cytosol and membrane (blue); LPS layer (white); BCV membrane (yellow); and an actin layer (magenta), observed only prior to vacuolar rupture. The BCV is surrounded by vesicles (orange). Additional views place BCV in cellular context. See also S2 Movie. Overall 15 FIB/SET data sets of invasion sites were acquired.