Figure 3.

APE1 interacts with Rac1 following infection. (A) Primary human ileal intestinal epithelial cells were infected with S. Typhimurium (MOI 10) or AIEC (MOI 100). Following infection, cells were fixed and the co-localization of APE1 and Rac1 was analyzed by proximity ligation assay (PLA), which produces a red fluorescent signal for proteins located within 40nm of each other. Significantly increased red fluorescence showing co-localization of APE1 and Rac1 was observed following infection with S. Typhimurium and AIEC, as shown by the quantification of nine different images as shown in (B). (C).T84 cells were pretreated with the Rac1 inhibitor NSC 23766 overnight and then infected with S. Typhimurium at MOI 10 for 1 h. Intracellular bacteria were quantified and show reduced numbers of S. Typhimurium in APE1-deficient cells pretreated with the Rac1 inhibitor. Pre-treatment of T84 (D) or HT-29 (E) cells with the Rac1-inhibitor NSC23766 limits internalization of AIEC strain LF82. (F) When instead of pretreating cells with the inhibitor, HT-29 cells were transfected with active Rac1 (V12) the levels of intracellular Salmonella bacteria in APE1 sufficient cells became similar to the levels observed in APE1-deficient cells after a 1 h infection. All error bars are represented as SEM. *p < 0.05; **p < 0.01; ***p < 0.001