Cultured intestinal epithelial cells were infected with S. Typhimurium strains expressing the phosphorylation site mutants AvrAS3C, AvrAS3D, AvrAS14D, or AvrAS14C from the AvrA native promoter in a low-copy plasmid, and the levels of effector protein translocation and JNK activation after infection were evaluated by western immunoblot analysis over time. This evidence concerns the gene MAPK8 and infection.