Identification of a protein secretory pathway for the secretion of heat-labile enterotoxin by an enterotoxigenic strain of Escherichia coli
AuthorTauschek, M; Gorrell, RJ; Strugnell, RA; Robins-Browne, RM
Source TitlePROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
PublisherNATL ACAD SCIENCES
AffiliationMicrobiology And Immunology
Document TypeJournal Article
CitationsTauschek, M., Gorrell, R. J., Strugnell, R. A. & Robins-Browne, R. M. (2002). Identification of a protein secretory pathway for the secretion of heat-labile enterotoxin by an enterotoxigenic strain of Escherichia coli. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 99 (10), pp.7066-7071. https://doi.org/10.1073/pnas.092152899.
Access StatusAccess this item via the Open Access location
Open Access at PMChttp://www.ncbi.nlm.nih.gov/pmc/articles/PMC124529
C1 - Journal Articles Refereed
Enterotoxigenic Escherichia coli (ETEC) is an enteric pathogen that causes cholera-like diarrhea in humans and animals. ETEC secretes a heat-labile enterotoxin (LT), which resembles cholera toxin, but the actual mechanism of LT secretion is presently unknown. We have identified a previously unrecognized type II protein secretion pathway in the prototypic human ETEC strain, H10407 (serotype O78:H11). The genes for this pathway are absent from E. coli K-12, although examination of the K-12 genome suggests that it probably once possessed them. The secretory pathway bears significant homology at the amino acid level to the type II protein secretory pathway required by Vibrio cholerae for the secretion of cholera toxin. With this in mind, we determined whether the homologous pathway of E. coli H10407 played a role in the secretion of LT. To this end, we inactivated the pathway by inserting a kanamycin-resistance gene into one of the genes (gspD) of the type II secretion pathway by homologous recombination. LT secretion by E. coli H10407 and the gspD mutant was assayed by enzyme immunoassay, and its biological activity was assessed by using Y-1 adrenal cells. This investigation showed that the protein secretory pathway is functional and necessary for the secretion of LT by ETEC. Our findings have revealed the mechanism for the secretion of LT by ETEC, which previously was unknown, and provide further evidence of close biological similarities of the LT and cholera toxin.
KeywordsBacteriology ; Infectious Diseases
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