The T3SS Effector EspT Defines a New Category of Invasive Enteropathogenic E. coli (EPEC) Which Form Intracellular Actin Pedestals
Figure 5
Rac1 and Wave2 are essential for EspT-mediated bacterial invasion.
(A) Swiss 3T3 cells were left untransfected or transfected with Non Targeting (NT) or Wave2 siRNA olgos, the ectopic expression vector pDSRed encoding Wave2ΔA, Wave2ΔBP or pRK5 expressing dominant negative Rac1 and Cdc42 and infected with JPN15, JPN15 expressing EspT or E110019. Mock transfected cells or cells transfected with dominant negative Cdc42 were efficiently invaded by both JPN15 expressing EspT and E110019. Cells transfected with dominant negative Rac1 were significantly more resistant to bacterial invasion. The Wave2ΔA and Wave2ΔBP constructs also had a potent dominant negative effect on bacterial internalization. (B) Quantification of bacterial invasion; cells which had 3 or more internalized bacteria were scored as invaded. 100 cells were counted in triplicate in three independent experiments. Results are displayed as mean±SEM.