Disease relevance of exoT

• The exoT open reading frame, cloned into a T7 expression system, produced a 53-kDa protein in Escherichia coli, termed Exo53, which reacted to antisera against exoenzyme S. A histidine-tagged derivative of recombinant Exo53 possessed approximately 0.2% of the ADP-ribosyltransferase activity of recombinant ExoS [1].
• RESULTS: For the cytotoxic strain, mutation of either exoU or exoT alone had little effect on virulence, whereas simultaneous mutation of both exoT and exoU or of exsA resulted in a significantly reduced capacity to cause corneal disease [2].
• We mapped the coding single nucleotide polymorphisms in four toxin genes-exoS, exoT, exoU, and exoY-of the Pseudomonas aeruginosa type III secretion system among several clinical isolates [3].
• With the addition of exoS and exoT to the molecular arsenal, questions concerning in vivo toxicity and target specificities of exoenzyme S can be directly addressed [4].

High impact information on exoT

• Uncoupling Crk signal transduction by Pseudomonas exoenzyme T [5].
• Clinical isolates that injure lung epithelium in vivo and that are cytotoxic in vitro possess exoT but lack exoS, suggesting that ExoS is not the cytotoxin responsible for the pathology and cell death measured in these assays [6].
• Therefore, we have systematically deleted the genes for the three known type III effector molecules (exoS, exoT, and exoY) in P. aeruginosa PAO1 and assayed the effect of the deletions, both singly and in combination, on cytotoxicity in vitro and in vivo [7].
• Complementation with exoT alone increased colonization ( approximately 3-log increase) and increased virulence to almost the same levels as wild-type or exoU-complemented infections [2].
• One representative clone contained the open reading frame exoT; this open reading frame encoded a protein of 457 amino acids which showed 75% amino acid identity to ExoS [1].

Biological context of exoT

• Inactivation of exoT in an allelic-replacement strain resulted in an Exo53-deficient phenotype without modifying the expression of ExoS [1].

Anatomical context of exoT

• Intracellular targeting of the Pseudomonas aeruginosa toxins exoenzyme S (ExoS) and exoenzyme T (ExoT) initially results in disruption of the actin microfilament structure of eukaryotic cells [8].
• ADP-ribosylation by exoenzyme T of Pseudomonas aeruginosa induces an irreversible effect on the host cell cytoskeleton in vivo [9].

References