Likely due to a side effect of intensive cell treatment, i.e. cell transfection and -infection in parallel, RSK1 phosphorylated on Ser-221 could regularly be observed in the nuclear fraction of cells that were both infected with WA-C(pTTSS+YopM) and treated with control siRNA (siCtrl; Fig 5B, middle panel). This evidence concerns the gene RPS6KA1 and infection.