Pseudomonas aeruginosa ExoS and ExoT

  • J. T. BarbieriEmail author
  • J. Sun
Part of the Reviews of Physiology, Biochemistry and Pharmacology book series (REVIEWS, volume 152)


ExoS and ExoT are bi-functional type-III cytotoxins of Pseudomonas aeruginosa that share 76% primary amino acid homology and contain N-terminal RhoGAP domains and C-terminal ADP-ribosylation domains. The Rho GAP activities of ExoS and ExoT appear to be biochemically and biologically identical, targeting Rho, Rac, and Cdc42. Expression of the RhoGAP domain in mammalian cells results in the disruption of the actin cytoskeleton and interference of phagocytosis. Expression of the ADP-ribosyltransferase domain of ExoS elicits a cytotoxic phenotype in cultured cells, while expression of ExoT appears to interfere with host cell phagocytic activity. Recent studies showed that ExoS and ExoT ADP-ribosylate different substrates. While ExoS has poly-substrate specificity and can ADP-ribosylate numerous host proteins, ExoT ADP-ribosylates a more restricted subset of host proteins including the Crk proteins. Protein modeling predicts that electrostatic interactions contribute to the substrate specificity of the ADP-ribosyltransferase domains of ExoS and ExoT.


Pseudomonas Aeruginosa Multidrug Transporter Focal Adhesion Complex Active Site Loop RhoGAP Domain 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



GTPase activating protein


Adenosine diphosphate ribose


Membrane localization domain


Factor activating exoenzyme S


CT-10 regulator of kinase


Soybean trypsin inhibitor


Guanine nucleotide exchange factor


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Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  1. 1.Microbiology and Molecular GeneticsMedical College of WisconsinMilwaukeeUSA

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