EspA, a protein secreted by enteropathogenic Escherichia coli, is required to induce signals in epithelial cells.
Enteropathogenic Escherichia coli (EPEC) is a leading cause of infant diarrhoea. EPEC mediates several effects on host epithelial cells, including activation of signal-transduction pathways, cytoskeletal rearrangement along with pedestal and attaching/effacing lesion formation. It has been previously shown that the EPEC eaeB (espB) gene encodes a secreted protein required for signal transduction and adherence, while eaeA encodes intimin, an EPEC membrane protein that mediates intimate adherence and contributes to focusing of cytoskeletal proteins beneath bacteria. DNA-sequence analysis of a region between eaeA and eaeB identified a predicted open reading frame (espA) that matched the amino-terminal sequence of a 25 kDa EPEC secreted protein. A mutant with a non-polar insertion in espA does not secrete this protein, activate epithelial cell signal transduction or cause cytoskeletal rearrangement. These phenotypes were complemented by a cloned espA gene. The espA mutant is also defective for invasion. It is concluded that espA encodes an EPEC secreted protein that is necessary for activating epithelial signal transduction, intimate contact, and formation of attaching and effacing lesions, processes which are central to pathogenesis.
Kenny
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B
Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada.
Lai
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LC
Finlay
B B
BB
Donnenberg
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MS
D018829:Adhesins, Bacterial; D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D001483:Base Sequence; D002352:Carrier Proteins; D004269:DNA, Bacterial; D004848:Epithelium / Q000382:microbiology; D004926:Escherichia coli / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D029968:Escherichia coli Proteins; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D016296:Mutagenesis; D015398:Signal Transduction
D018829:Adhesins, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D004269:DNA, Bacterial; C087863:EaeB protein, E coli; D029968:Escherichia coli Proteins; C102051:EspA protein, E coli; C073819:eaeA protein, E coli