title: Pasteurella multocida toxin increases endothelial permeability via Rho kinase and myosin light chain phosphatase.
abstract: Pasteurella multocida toxin (PMT) has been shown to induce actin reorganization through activation of the GTPase Rho. Here we investigated the involvement of the Rho target proteins Rho kinase and myosin light chain (MLC) phosphatase in the PMT-induced increase in endothelial permeability and the underlying actin reorganization of endothelial cells. Stimulation of endothelial layers with PMT enhanced transendothelial permeability > 10-fold, and this was abolished by pretreatment with the specific Rho inactivator C3 transferase from Clostridium botulinum. The PMT-induced increase in endothelial permeability was associated with 1) inactivation of MLC phosphatase, 2) an increase in MLC phosphorylation, and 3) endothelial cell retraction and actin stress fiber formation. PMT-stimulated actin reorganization could be prevented by 1) pretreatment of cells with C3 transferase, 2) microinjection of the Rho binding domain and the pleckstrin homology domain of Rho kinase, and 3) microinjection of constitutively active MLC phosphatase. Together, these results suggest that PMT activates Rho/Rho kinase, which inactivates MLC phosphatase. The resulting increase in MLC phosphorylation causes endothelial cell retraction and a rise in endothelial permeability.
authors.affiliation: Institut für Prophylaxe und Epidemiologie der Kreislaufkrankheiten, Universität München, Germany. messler@klp.med.uni-muenchen.de
authors.forename: M
authors.initials: M
authors.lastname: Essler
authors.forename: K
authors.initials: K
authors.lastname: Hermann
authors.forename: M
authors.initials: M
authors.lastname: Amano
authors.forename: K
authors.initials: K
authors.lastname: Kaibuchi
authors.forename: J
authors.initials: J
authors.lastname: Heesemann
authors.forename: P C
authors.initials: PC
authors.lastname: Weber
authors.forename: M
authors.initials: M
authors.lastname: Aepfelbacher
mesh_terms: D001426:Bacterial Proteins; D001427:Bacterial Toxins / Q000276:immunology / Q000494:pharmacology*; D002463:Cell Membrane Permeability / Q000276:immunology*; D048429:Cell Size / Q000276:immunology; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000201:enzymology* / Q000276:immunology*; D004789:Enzyme Activation / Q000276:immunology; D020558:GTP Phosphohydrolases / Q000502:physiology; D019204:GTP-Binding Proteins / Q000502:physiology; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D018994:Myosin Light Chains / Q000378:metabolism; D043263:Myosin-Light-Chain Phosphatase; D016979:Pasteurella multocida / Q000276:immunology*; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors / Q000502:physiology*; D010766:Phosphorylation; D054648:Protein Phosphatase 2; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D014471:Umbilical Veins; D020741:rho GTP-Binding Proteins; D054460:rho-Associated Kinases
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D047908:Intracellular Signaling Peptides and Proteins; D018994:Myosin Light Chains; C062258:Pasteurella multocida toxin; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D010749:Phosphoprotein Phosphatases; D054648:Protein Phosphatase 2; D043263:Myosin-Light-Chain Phosphatase; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; D020741:rho GTP-Binding Proteins