Fig. 4.

EspT-induced cytoskeletal rearrangements are dependent on Rac-1 and Cdc42. A. Swiss 3T3 cells were transfected with the dominant negative forms of RhoA, RhoG, Rac-1 and Cdc42 18 h prior to infection for 90 min with E2348/69 expressing EspT. Actin was stained with Oregon green phalloidin, the myc-tagged RhoA, Rac-1 and Cdc42 dominant negatives were stained with a myc tag monoclonal antibody, RhoG was detected via its GFP tag and E2348/69 was visualized using a rabbit O127 antibody. Actin pedestals were observed beneath all adherent bacteria. Lamellipodia were observed in cells transfected with dominant negative RhoA^N19 and the RhoG^N17. The majority of cells transfected with dominant negative Rac-1^N17 did not display lamellipodia. Dominant negative Cdc42^N17 reduced the number of cells expressing lamellipodia as well as reducing the extent of the lamellipodia compared with the mock or dominant negative RhoA^N19 and RhoG^N17. B. Quantification of lamellipodia in transfected Swiss 3T3 after 90 min infection with E2348/69 expressing EspT. One hundred cells were counted in triplicate in three independent experiments. Results are displayed as mean ± SEM.