Figure 9.

Model depicting the effect of EPEC on apical-basal polarity. Polarized epithelial cells consist of the apical membrane facing the lumen and the basolateral domain contacting the underlying basement membrane. The apical polarity complex Crb (Crb3/Pals1/Patj) localizes at the TJ (Control). i) During EPEC infection, the injected EPEC effectors, including EspF and Map, induce the endocytosis of polarity proteins Crb3 and Pals1 and the basolateral protein Na⁺/K⁺ ATPase. ii) Increased endocytosis of Crb3, Pals1 and likely other polarity proteins leads to a loss in the apical-basal polarity, as demonstrated by the redistribution of Na⁺/K⁺ ATPase to the apical membrane.