Figure 3. EspFU induces actin pedestal formation.
A. Cells expressing the TirΔC, TirΔC-R2 or TirΔC-R2 VL* (with N-terminal HA-tags) were challenged with E. coli expressing intimin, and stained with anti-HA antibody (green) and Alexa568-phalloidin (red, left panels) or anti-N-WASP antibody (red, right panels). Colocalization is yellow in merged images. The % of transfected cells harboring at least five F-actin foci was quantified (Actin Assembly Index). Bacteria were visualized by DAPI staining. B. Cells expressing Tir-repeat proteins were challenged with anti-Tir antibody and S. aureus particles and Actin Assembly Index was determined. In A and B data represent mean +/− SD from at least two samples with 20-50 cells examined per sample.