S. flexneri intercellular lifecycle

Shigella flexneri intercellular lifecycle

  1. Invasion of an epithelial cell
  2. Escape from the phagosome
  3. Replication in the cytosol
  4. Production of actin tail and movement 
  5. Formation of plasma membrane protrusion
  6. Resolution of protrusion into double membrane vacuole
  7. Escape from double membrane vacuole

Green bacteria indicate the stages at which type 3 secretion is required.

S. flexneri form actin tails

Shigella flexneri polymerize actin to form "tails" behind the bacteria. The forces generated from polymerizing actin enable the bacteria to move in the cell.

S. flexneri is green; actin is red; the cell nucleus is blue.