FIG. 4.

The conserved residue R149 contributes to the cell rounding activity of ExoT. HeLa cells were infected with isogenic strains of P. aeruginosa at an MOI of 25 for 6 h. (A) No bacteria; (B) PA103pscJ::Tn5; (C) PA103ΔU+pUCP20; (D) PA103ΔUΔT+pUCP20; (E) PA103ΔUΔT+pExoS; (F) PA103ΔUΔT+pExoT; (G) PA103ΔUΔT+pExoT(R149G); (H) PA103ΔUΔT+pExoT(R149K). Infected cells were observed by phase-contrast microscopy. The larger images were captured at a ×100 magnification, and the inset images were captured at a ×200 magnification using a CCD camera and SPOT imaging software.