Figure 1.

Extended presence of internalized SK3842 alters major host cell signalling. (a) Levels of survival-related proteins: (i) Mcl1, Bim, Puma and (ii) Caspase 3 and Caspase 9. (b) Changes in indicated proteins of major signal transduction modules: (i) MAPK, (ii) AKT, (iii) NF-κB and (iv) β-catenin. (c) NF-κB and β-catenin levels in cytoplasmic and nuclear fractions. (d) Luciferase reporter assay of NF-κB and β-catenin transcription activity. (e) mRNA expression of inflammatory cytokines. (f) Effect of bacterial virulence factors on expression of survival-related host proteins in (i–ii) haemolysin-overexpressing SK3842 and (iii) invasive variant of O157:H7 strain. (i) Expression of Bim, Puma and activated caspase 3; (ii) Luciferase reporter assay of NF-κB and β-catenin; (iii) Expression of Bim and Puma (after one infection). Con=control Caco-2, Inf=SK3842-infected Caco-2. Data=Mean±S.D. (three experiments); *P<0.05, **P<0.01 and ***P<0.001 versus control