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Molecular dissection of protein–protein interactions between integrin α5β1 and the Helicobacter pylori Cag type IV secretion system
Author(s) -
Koelblen Thomas,
Bergé Célia,
Cherrier Mickaël V.,
Brillet Karl,
JimenezSoto Luisa,
Ballut Lionel,
Takagi Junichi,
Montserret Roland,
Rousselle Patricia,
Fischer Wolfgang,
Haas Rainer,
Fronzes Rémi,
Terradot Laurent
Publication year - 2017
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/febs.14299
Subject(s) - caga , ectodomain , integrin , secretion , biology , pilus , receptor , bacterial adhesin , microbiology and biotechnology , virulence , gene , biochemistry
The more severe strains of the bacterial human pathogen Helicobacter pylori produce a type IV secretion system ( cag T4 SS ) to inject the oncoprotein cytotoxin‐associated gene A (CagA) into gastric cells. This syringe‐like molecular apparatus is prolonged by an external pilus that exploits integrins as receptors to mediate the injection of CagA. The molecular determinants of the interaction of the cag T4 SS pilus with the integrin ectodomain are still poorly understood. In this study, we have used surface plasmon resonance ( SPR ) to generate a comprehensive analysis of the protein–protein interactions between purified CagA, CagL, CagI, CagY repeat domain II (Cag Y RRII ), CagY C‐terminal domain (Cag Y B 10 ) and integrin α5β1 ectodomain (α5β1 E ) or headpiece domain (α5β1 HP ). We found that CagI, CagA, CagL and Cag Y B 10 but not Cag Y RRII were able to interact with α5β1 E with affinities similar to the one observed for α5β1 E interaction with its physiological ligand fibronectin. We further showed that integrin activation and its associated conformational change increased CagA, CagL and Cag Y B 10 affinities for the receptor. Furthermore, CagI did not interact with integrin unless the receptor was in open conformation. CagI, CagA but not CagL and Cag Y B 10 interacted with the α5β1 HP . Our SPR study also revealed novel interactions between CagA and CagL, CagA and Cag Y B 10 , and CagA and CagI. Altogether, our data map the network of interactions between host‐cell α5β1 integrin and the cag T4 SS proteins and suggest that activation of the receptor promotes interactions with the secretion apparatus and possibly CagA injection.