MAPK3 and inflammatory bowel disease: 5-ASA mediated inhibition of the master regulator PAK1 contributes to attenuation of multiple signaling pathways such as Wnt/β-catenin, ERK1/2, AKT1, mTOR, NF-kB and induction of cell cycle arrest.32,36,50 EspG has been shown to activate PAKs, and PAK1 has recently been identified as an important driver of colitis in IBD in an integrated in vivo multiomics study.31,35 Therefore, we investigated the effect of 5-ASA on aEPEC induced epithelial IL-8 secretion and PAK mRNA expression.