Figure 3.
CEACAM3- but not CEACAM6-mediated internalization of gonococci depends on the small GTPase Rac. (A) 293 cells cotransfected with Cdc42 N17 or Rac N17 and either CEACAM3 or CEACAM6 were infected with OpaCEA gonococci, and the number of internalized bacteria was determined in gentamicin protection assays. The graph shows mean values ± SDs of three independent experiments done in triplicate. Western blotting of whole cell lysates (WCL) with anti–myc tag antibody demonstrates expression of transfected Cdc42 N17 and Rac N17, respectively. (B) 293 cells, transfected with CEACAM3 or CEACAM6, were infected with OpaCEA N. gonorrhoeae for 1 h, fixed, and stained with polyclonal antibodies against gonococci and monoclonal antibodies against Rac. In CEACAM3-transfected cells, Rac is recruited to the site of bacteria–cell interaction (arrowhead).