FIG 1.

Thapsigargin increases NF-κB activation in response to S. Typhimurium independent of bacterial invasion. (A and B) HeLa57A cells were pretreated with thapsigargin (Thp) (0.1 and 1 μM) (A) or tunicamycin (Tun) (0.1 and 1 μg/ml) (B) and infected with the S. Typhimurium wild-type strain SL1344, the SopE-positive sipA sopB sopE2 mutant strain, and the sipA sopB sopE2 sopE mutant strain. The response induced by S. Typhimurium wild-type strain SL1344 was set at 100%. Data represent the means ± standard errors from at least three independent experiments in triplicate. (C) Cells were infected at an MOI of 10 for 1 h, and extracellular bacteria were killed with gentamicin for 90 min. Recovered bacterial numbers were standardized to the number of bacteria in the inoculum. Data represent the means ± standard errors from three independent experiments in duplicate. One-way analysis of variance (ANOVA) followed by Dunnett’s multiple-comparison test was used to determine statistical significance. A P value of <0.05 was taken to be significant (indicated by an asterisk).