I. Simonovic et al., Enteropathogenic Escherichia coli activates ezrin, which participates in disruption of tight junction barrier function, INFEC IMMUN, 69(9), 2001, pp. 5679-5688
Enteropathogenic Escherichia coli (EPEC) is an important human intestinal p
athogen, especially in infants. EPEC adherence to intestinal epithelial cel
ls induces the accumulation of a number of cytoskeletal proteins beneath th
e bacteria, including the membrane-cytoskeleton linker ezrin. Evidence sugg
ests that ezrin can participate in signal transduction. The aim of this stu
dy was to determine whether ezrin is activated following EPEC infection and
if it is involved in the cross talk with host intestinal epithelial cells.
We show here that following EPEC attachment to intestinal epithelial cells
there was significant phosphorylation of ezrin, first on threonine and lat
er on tyrosine residues. A significant increase in cytoskeleton-associated
ezrin occurred following phosphorylation, suggesting activation of this mol
ecule. Nonpathogenic E. coli and EPEC strains harboring mutations in type I
II secretion failed to elicit this response. Expression of dominant-negativ
e ezrin significantly decreased the EPEC-elicited association of ezrin with
the cytoskeleton and attenuated the disruption of intestinal epithelial ti
ght junctions. These results suggest that ezrin is involved in transducing
EPEC-initiated signals that ultimately affect host physiological functions.