ATTACHING AND EFFACING OF HOST-CELLS BY ENTEROPATHOGENIC ESCHERICHIA-COLI IN THE ABSENCE OF DETECTABLE TYROSINE KINASE MEDIATED SIGNAL-TRANSDUCTION

An unusual mutant of enteropathogenic E. coli (EPEC), deficient in its ability to invade host cells, was evaluated. The gene interrupted by the transposon in this mutant was located within a region of the EPEC chromosome devoted to secretion of proteins required for signal transd uction. The mutant did not secrete detectable levels of the EspB prote in, previously shown to be required for attaching and effacing, and di d not induce detectable tyrosine phosphorylation of a 90 kDa host cell protein, previously associated with attaching and effacing and invasi on. No quantitative or qualitative defect in the ability of the mutant to induce attaching and effacing effects was observed. Moreover, atta ching and effacing by wild-type EPEC was unaffected by high doses of t he tyrosine kinase inhibitor genistein. These results indicate that at taching and effacing activity can occur in the absence of detectable E spB secretion and tyrosine kinase mediated signal transduction. (C) 19 96 Academic Press Limited