Figure 5. Rac Inactivation Inhibits Bacterial Uptake but Not Pore Formation or Translocation.

Hela cells were treated for 6h with Rac inhibitor NSC23766 (100μM) in 5% serum-DMEM, or with 5% serum-DMEM alone. NSC23766-treated and untreated cells were infected with YP27 (yopEHJ) or the uptake-deficient strain YP50/pAY66 (yopEHJ,yadA,inv/psaABC). The percentage of internalized bacteria was assessed one hour after infection by double staining immunofluorescence, as described in Material and Methods (A). LDH released by uninfected cells or by cells infected with YP27 or YP29 (yopEHJB), in the presence or absence of the Rac inhibitor, was assessed as described in Figure 1 (B). The amount of translocated YopE in the cell lysate of cells infected with wild type (YP126) or yopB (YP18) was analyzed by immunoblotting as described Figure 2 (C).