RAC1 and infection: Using GST-pulldown based assays we could demonstrate that infection with EPEC-wt, but not with EPEC-escV (escV::Tn5kan; T3SS deficient), or EPEC-∆espH, decreased the Cdc42 and Rac1 activity levels in the infected cells (Figure 3a), suggesting that EspH is the effector that suppresses the RhoGTPases.