Abstract
Bladder infections caused by uropathogenic Escherichia coli (UPEC) depends on the ability of E. coli to express type 1 pili. The adhesive component of the pilus, FimH, mediates the invasion of E. coli into the bladder epithelium, a mechanism that facilitates the survival and persistence of E. coli in the bladder. The invasion mechanism requires actin polymerization, focal adhesion kinase phosphorylation and PI 3-kinase activation as well as the formation of FAK/PI 3-kinase and downstream vinculin/alpha-actinin complexes. In this study, we report a role for Rho-GTPase family members, namely RhoA, Cdc42 and Rac1, in the invasion process. Internalization of type 1-piliated E. coli (fimH+) and FimH-coated micro-spheres was inhibited by compactin, a pan-Rho-GTPase inhibitor and dominant negative isoforms of Rac1 and Cdc42. Expression of active Rac1 induced an internalization of E. coli that was insensitive to wortmannin and genistein. Expression of constitutively active Cdc42 induced the formation of FAK/PI 3-kinase and vinculin/alpha-actinin complexes whereas active Rac1 induced only a vinculin/alpha-actinin complex. Taken together, these data suggest that FimH-mediated invasion is dependent on GTP-binding protein activity that involves Cdc42 and PI 3-kinase activation probably upstream of Rac1.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Adhesins, Bacterial / metabolism
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Adhesins, Escherichia coli*
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Animals
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Biological Transport / physiology*
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Cell Line
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Cystitis / microbiology
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Escherichia coli / metabolism
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Escherichia coli / pathogenicity*
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Fimbriae Proteins*
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Fimbriae, Bacterial / metabolism*
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Focal Adhesion Kinase 1
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Focal Adhesion Protein-Tyrosine Kinases
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Humans
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Lovastatin / analogs & derivatives*
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Lovastatin / pharmacology
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Microscopy, Fluorescence
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Microspheres
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Models, Biological
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Phosphatidylinositol 3-Kinases / metabolism
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Phosphoinositide-3 Kinase Inhibitors
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Protein-Tyrosine Kinases / metabolism
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Receptor Protein-Tyrosine Kinases / antagonists & inhibitors
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Receptor Protein-Tyrosine Kinases / metabolism
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Urinary Bladder / cytology
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Urinary Bladder / microbiology*
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Urothelium / cytology
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Urothelium / metabolism
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Urothelium / microbiology*
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cdc42 GTP-Binding Protein / metabolism
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rac1 GTP-Binding Protein / metabolism
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rho GTP-Binding Proteins / antagonists & inhibitors
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rho GTP-Binding Proteins / metabolism*
Substances
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Adhesins, Bacterial
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Adhesins, Escherichia coli
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Phosphoinositide-3 Kinase Inhibitors
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fimH protein, E coli
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Fimbriae Proteins
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mevastatin
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Lovastatin
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Protein-Tyrosine Kinases
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Receptor Protein-Tyrosine Kinases
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Focal Adhesion Kinase 1
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Focal Adhesion Protein-Tyrosine Kinases
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PTK2 protein, human
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cdc42 GTP-Binding Protein
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rac1 GTP-Binding Protein
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rho GTP-Binding Proteins