ADP-ribosylation by Exoenzyme T of Pseudomonas Aeruginosa Induces an Irreversible Effect on the Host Cell Cytoskeleton in Vivo

FEMS Microbiol Lett. 2004 May 1;234(1):87-91. doi: 10.1016/j.femsle.2004.03.014.


Pseudomonas aeruginosa utilises a type III secretion system (TTSS) to introduce exoenzyme S and exoenzyme T into host cells to subvert host cell signalling and thereby promote infection. In this study, we have employed the heterologous TTSS of Yersinia to deliver different mutants of ExoT into HeLa cells. Wild-type ExoT and ExoT variants expressing either GAP (GTPase activating protein) or ADP-ribosyltransferase activity mediated changes in cell morphology, which correlated to disruption of the actin microfilaments of the infected cells. ExoT expressing ADP-ribosylating activity gave an irreversible effect on HeLa cell morphology, while ExoT expressing only GAP activity displayed a reversible effect where the cells regained normal cell morphology after killing of the infecting bacteria. This shows that ExoT can modify and inactivate host cell proteins involved in maintaining the actin cytoskeleton in vivo by two independent mechanisms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ADP Ribose Transferases / genetics
  • ADP Ribose Transferases / metabolism*
  • Actin Cytoskeleton / metabolism
  • Actin Cytoskeleton / ultrastructure
  • Actins / metabolism
  • Adenosine Diphosphate Ribose / metabolism*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Cell Line
  • Cell Size
  • Cloning, Molecular
  • Cytoskeleton / metabolism*
  • Cytoskeleton / ultrastructure
  • GTPase-Activating Proteins
  • Gene Expression
  • Genes, Bacterial
  • HeLa Cells
  • Humans
  • Microscopy
  • Microscopy, Fluorescence
  • Mutation
  • Protein Structure, Tertiary
  • Protein Transport
  • Pseudomonas aeruginosa / enzymology*
  • Pseudomonas aeruginosa / pathogenicity
  • Recombinant Proteins / metabolism
  • Signal Transduction
  • Yersinia pseudotuberculosis / genetics
  • Yersinia pseudotuberculosis / metabolism


  • Actins
  • Bacterial Proteins
  • ExoT protein, Pseudomonas aeruginosa
  • GTPase-Activating Proteins
  • Recombinant Proteins
  • Adenosine Diphosphate Ribose
  • ADP Ribose Transferases