Multiple domains are required for the toxic activity of Pseudomonas aeruginosa ExoU. J Bacteriol 2001 Jul;183(14):4330-44
Date
06/22/2001Pubmed ID
11418575Pubmed Central ID
PMC95324DOI
10.1128/JB.183.14.4330-4344.2001Scopus ID
2-s2.0-0034977803 (requires institutional sign-in at Scopus site) 57 CitationsAbstract
Expression of ExoU by Pseudomonas aeruginosa is correlated with acute cytotoxicity in a number of epithelial and macrophage cell lines. In vivo, ExoU is responsible for epithelial injury. The absence of a known motif or significant homology with other proteins suggests that ExoU may possess a new mechanism of toxicity. To study the intracellular effects of ExoU, we developed a transient-transfection system in Chinese hamster ovary cells. Transfection with full-length but not truncated forms of ExoU inhibited reporter gene expression. Inhibition of reporter activity after cotransfection with ExoU-encoding constructs was correlated with cellular permeability and death. The toxicity of truncated versions of ExoU could be restored by coexpression of the remainder of the molecule from separate plasmids in trans. This strategy was used to map N- and C-terminal regions of ExoU that are necessary but not sufficient for toxicity. Disruption of a middle region of the protein reduces toxicity. This portion of the molecule is postulated to allow the N- and C-terminal regions to functionally complement one another. In contrast to ExoS and ExoT, native and recombinant ExoU molecules do not oligomerize or form aggregates. The complex domain structure of ExoU suggests that, like other P. aeruginosa-encoded type III effectors (ExoS and ExoT), ExoU toxicity may result from a molecule that possesses more than one activity.
Author List
Finck-Barbançon V, Frank DWAuthor
Dara W. Frank PhD Professor in the Microbiology and Immunology department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AnimalsBacterial Proteins
Bacterial Toxins
Binding Sites
CHO Cells
Cell Membrane Permeability
Cricetinae
Cytotoxins
Gene Expression
Genes, Reporter
Green Fluorescent Proteins
Luminescent Proteins
Oligopeptides
Pseudomonas aeruginosa
Recombinant Fusion Proteins
