ExoT of cytotoxic Pseudomonas aeruginosa prevents uptake by corneal epithelial cells - PubMed (original) (raw)

ExoT of cytotoxic Pseudomonas aeruginosa prevents uptake by corneal epithelial cells

B A Cowell et al. Infect Immun. 2000 Jan.

Free PMC article

Abstract

The presence of invasion-inhibitory activity that is regulated by the transcriptional activator ExsA of cytotoxic Pseudomonas aeruginosa has previously been proposed. The results of this study show that both ExoT and ExoS, known type III secreted effector proteins of P. aeruginosa that are regulated by ExsA, possess this activity. Invasion was reduced 94.4% by ExoT and 96.0% by ExoS. Invasion-inhibitory activity is not linked to ADP-ribosylation activity, at least for ExoS, since a noncatalytic mutant also inhibits uptake by an epithelial cell line (invasion was reduced 96. 0% by ExoSE381A).

PubMed Disclaimer

Figures

FIG. 1

PA103_exoU_ inhibits uptake of invasive strains of P. aeruginosa. PA103_exoU_ was coincubated with invasive strains of P. aeruginosa during infection of RCE cells, and uptake was quantified. PA103_exoU_ (□) inhibited the invasion of all strains assayed when coincubated with 6294 (■) (a), 6487 (░⃞) (b), and PA103_exoUexsA_([Image: see text]) (c). PA103_exoUexsA_ (█) did not inhibit invasion when coincubated with 6294 (■) (d).

FIG. 2

Uptake of PA103_exoU_ mutants by RCE cells. Bacterial strains were incubated for 3 h with RCE cells before the determination of intracellular bacteria. PA103_exoU_ is noninvasive, and further mutation of exsA or exoT_resulted in an invasive phenotype. Complementation with_exoT, exoS, or _exoS_E381A restored invasion-inhibitory activity.

References

1. Altschul S F, Madden T L, Schäffer A A, Zhang J, Zhang Z, Miller W, Lipman D J. Gapped BLAST and PSI-BLAST: a new generation of protein database search programs. Nucleic Acids Res. 1997;25:3389–3402. -PMC -PubMed
1. Andersson K, Carballeira N, Magnusson K-E, Persson C, Stendahl O, Wolf-Watz H, Fällman M. YopH of Yersinia pseudotuberculosisinterrupts early phosphotyrosine signaling associated with phagocytosis. Mol Microbiol. 1996;20:1057–1069. -PubMed
1. Bölin I, Wolf-Watz H. The plasmid-encoded Yop2b protein of Yersinia pseudotuberculosisis a virulence determinant regulated by calcium and temperature at the level of transcription. Mol Microbiol. 1988;2:237–245. -PubMed
1. Cowell B A, Wu C, Fleiszig S M J. Use of an animal model in studies of bacterial corneal infection. Inst Lab Anim Res J. 1999;40:43–50. -PubMed
1. Evans D J, Frank D W, Finck-Barbançon V, Wu C, Fleiszig S M J. Pseudomonas aeruginosainvasion and cytotoxicity are independent events, both of which involve protein tyrosine kinase activity. Infect Immun. 1998;66:1453–1459. -PMC -PubMed

ExoT of cytotoxic Pseudomonas aeruginosa prevents uptake by corneal epithelial cells - PubMed (original) (raw)