title: HtrA-mediated E-cadherin cleavage is limited to DegP and DegQ homologs expressed by gram-negative pathogens.
abstract: The serine proteases HtrA/DegP secreted by the human gastrointestinal pathogens Helicobacter pylori (H. pylori) and Campylobacter jejuni (C. jejuni) cleave the mammalian cell adhesion protein E-cadherin to open intercellular adhesions. A wide range of bacteria also expresses the HtrA/DegP homologs DegQ and/or DegS, which significantly differ in structure and function.
  
  
  
  E-cadherin shedding was investigated in infection experiments with the Gram-negative pathogens H. pylori, enteropathogenic Escherichia coli (EPEC), Salmonella enterica subsp. Enterica (S. Typhimurium), Yersinia enterocolitica (Y. enterocolitica), and Proteus mirabilis (P. mirabilis), which express different combinations of HtrAs. Annotated wild-type htrA/degP, degQ and degS genes were cloned and proteolytically inactive mutants were generated by a serine-to-alanine exchange in the active center. All HtrA variants were overexpressed and purified to compare their proteolytic activities in casein zymography and in vitro E-cadherin cleavage experiments.
  
  
  
  Infection of epithelial cells resulted in a strong E-cadherin ectodomain shedding as reflected by the loss of full length E-cadherin in whole cell lysates and formation of the soluble 90 kDa extracellular domain of E-cadherin (NTF) in the supernatants of infected cells. Importantly, comparing the caseinolytic and E-cadherin cleavage activities of HtrA/DegP, DegQ and DegS proteins revealed that DegP and DegQ homologs from H. pylori, S. Typhimurium, Y. enterocolitica, EPEC and P. mirabilis, but not activated DegS, cleaved E-cadherin as a substrate in vitro.
  
  
  
  These data indicate that E-cadherin cleavage is confined to HtrA/DegP and DegQ proteins representing an important prevalent step in bacterial pathogenesis.
authors.affiliation: Division of Microbiology, Department of Molecular Biology, Paris-Lodron University of Salzburg, Billroth Str. 11, A-5020, Salzburg, Austria.
authors.forename: Carmen M
authors.initials: CM
authors.lastname: Abfalter
authors.affiliation: Division of Microbiology, Department of Molecular Biology, Paris-Lodron University of Salzburg, Billroth Str. 11, A-5020, Salzburg, Austria.
authors.forename: Maria
authors.initials: M
authors.lastname: Schubert
authors.affiliation: Division of Microbiology, Department of Molecular Biology, Paris-Lodron University of Salzburg, Billroth Str. 11, A-5020, Salzburg, Austria.
authors.forename: Camilla
authors.initials: C
authors.lastname: Götz
authors.affiliation: Division of Microbiology, Department of Molecular Biology, Paris-Lodron University of Salzburg, Billroth Str. 11, A-5020, Salzburg, Austria.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Schmidt
authors.affiliation: Division of Microbiology, Department of Molecular Biology, Paris-Lodron University of Salzburg, Billroth Str. 11, A-5020, Salzburg, Austria.
authors.forename: Gernot
authors.initials: G
authors.lastname: Posselt
authors.affiliation: Division of Microbiology, Department of Molecular Biology, Paris-Lodron University of Salzburg, Billroth Str. 11, A-5020, Salzburg, Austria. silja.wessler@sbg.ac.at.
authors.forename: Silja
authors.identifier: 0000-0001-7011-6162
authors.initials: S
authors.lastname: Wessler
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015820:Cadherins / Q000378:metabolism*; D002460:Cell Line; D054308:Enteropathogenic Escherichia coli / Q000201:enzymology / Q000502:physiology; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism*; D006090:Gram-Negative Bacteria / Q000737:chemistry / Q000201:enzymology* / Q000502:physiology*; D016905:Gram-Negative Bacterial Infections / Q000378:metabolism* / Q000473:pathology; D006360:Heat-Shock Proteins / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D033903:Periplasmic Proteins / Q000737:chemistry / Q000378:metabolism*; D059748:Proteolysis; D016415:Sequence Alignment; D012697:Serine Endopeptidases / Q000737:chemistry / Q000378:metabolism*
chemical_list: D015820:Cadherins; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; D033903:Periplasmic Proteins; C061682:DegP protease; C098059:DegQ protein, E coli; D012697:Serine Endopeptidases
keywords: DegP; DegQ; E-cadherin; HtrA