title: Pathogenicity island-dependent activation of Rho GTPases Rac1 and Cdc42 in Helicobacter pylori infection.
abstract: Helicobacter pylori has been identified as the major aetiological agent in the development of chronic gastritis and duodenal ulcer, and it plays a role in the development of gastric carcinoma. Attachment of H. pylori to gastric epithelial cells leads to nuclear and cytoskeletal responses in host cells. Here, we show that Rho GTPases Rac1 and Cdc42 were activated during infection of gastric epithelial cells with either the wild-type H. pylori or the mutant strain cagA. In contrast, no activation of Rho GTPases was observed when H. pylori mutant strains (virB7 and PAI) were used that lack functional type IV secretion apparatus. We demonstrated that H. pylori-induced activation of Rac1 and Cdc42 led to the activation of p21-activated kinase 1 (PAK1) mediating nuclear responses, whereas the mutant strain PAI had no effect on PAK1 activity. Activation of Rac1, Cdc42 and PAK1 represented a very early event in colonization of gastric epithelial cells by H. pylori. Rac1 and Cdc42 were recruited to the sites of bacterial attachment and are therefore probably involved in the regulation of local and overall cytoskeleton rearrangement in host cells. Finally, actin rearrangement and epithelial cell motility in H. pylori infection depended on the presence of a functional type IV secretion system encoded by the cag pathogenicity island (PAI).
authors.affiliation: Max-Planck-Institut für Infektionsbiologie, Abteilung Molekulare Biologie, Schumannstrasse 21/22, D-10117 Berlin, Germany.
authors.forename: Y
authors.initials: Y
authors.lastname: Churin
authors.forename: E
authors.initials: E
authors.lastname: Kardalinou
authors.forename: T F
authors.initials: TF
authors.lastname: Meyer
authors.forename: M
authors.initials: M
authors.lastname: Naumann
mesh_terms: D000942:Antigens, Bacterial; D001422:Bacterial Adhesion / Q000502:physiology; D001426:Bacterial Proteins / Q000235:genetics; D002465:Cell Movement; D002478:Cells, Cultured; D004789:Enzyme Activation; D004847:Epithelial Cells / Q000382:microbiology; D005753:Gastric Mucosa / Q000166:cytology / Q000382:microbiology; D016481:Helicobacter Infections / Q000378:metabolism* / Q000382:microbiology; D016480:Helicobacter pylori / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity*; D006801:Humans; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism*; D054462:p21-Activated Kinases; D020830:rac1 GTP-Binding Protein / Q000378:metabolism*
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C080866:cagA protein, Helicobacter pylori; C515903:PAK1 protein, human; D017346:Protein Serine-Threonine Kinases; D054462:p21-Activated Kinases; D020764:cdc42 GTP-Binding Protein; D020830:rac1 GTP-Binding Protein