Effector molecule Activated by Mode of action Effect on apoptosis NEMO TNF-a, IL-1b NF-kB activation á PUMA NFκB/TNF-α TNF-induced disturbance of IEC integrity á GBP-1 IFN-γ Stabilization of intercellular junctions â ErbB4 TNF-α, TACE Akt phosphorylation â Dkk-1 IFN-γ Antagonization of Wnt/β-catenin pathway á GCC enterotoxins conversion of GTP to cGMP, Akt inhibition â PHD hypoxia degradation of HIFs, hydroxylation of IKK-β á HIFs hypoxia induction of a stabilizing gene expression profile â sphingomyelin sphingomyelinase caspase activation, Bcl2 inactivation á phosphatidylcholine   inhibition of proinflammatory cytokines â

Table 1: Summary of the described effector molecules and the mechanisms through which they regulate IEC apoptosis.