B. Kenny et Bb. Finlay, PROTEIN SECRETION BY ENTEROPATHOGENIC ESCHERICHIA-COLI IS ESSENTIAL FOR TRANSDUCING SIGNALS TO EPITHELIAL-CELLS, Proceedings of the National Academy of Sciences of the United Statesof America, 92(17), 1995, pp. 7991-7995
Enteropathogenic Escherichia coli (EPEC), a major cause of pediatric d
iarrhea, adheres to epithelial cells and activates host cell signal tr
ansduction pathways. We have identified five proteins that are secrete
d by EPEC and show that this secretion process is critical for trigger
ing signal transduction events in epithelial cells. Protein secretion
occurs via two pathways: one secretes a 110-kDa protein and the other
mediates export of the four remaining proteins. Secretion of all five
proteins was regulated by temperature and the perA locus, two factors
which regulate expression of other known EPEC virulence factors. Amino
-terminal sequence analysis of the secreted polypeptides identified on
e protein (37 kDa) as the product of the eaeB gene, a genetic locus pr
eviously shown to be necessary for signal transduction. A second prote
in (39 kDa) showed significant homology with glyceraldehyde-3-phosphat
e dehydrogenase, while the other three proteins (110, 40, and 25 kDa)
were unique. The secreted proteins associated with epithelial cells, a
nd EaeB became resistant to protease digestion upon association, sugge
sting that intimate interactions are required for transducing signals.