The VacA toxin of Helicobacter pylori identifies a new intermediate filament-interacting protein.
The VacA toxin produced by Helicobacter pylori acts inside cells and induces the formation of vacuoles arising from late endosomal/lysosomal compartments. Using VacA as bait in a yeast two-hybrid screening of a HeLa cell library, we have identified a novel protein of 54 kDa (VIP54), which interacts specifically with VacA, as indicated by co-immunoprecipitation and binding experiments. VIP54 is expressed in cultured cells and many tissues, with higher expression in the brain, muscle, kidney and liver. Confocal immunofluorescence microscopy with anti-VIP54 affinity- purified antibodies shows a fibrous pattern typical of intermediate filaments. Double label immunofluorescence performed on various cell lines with antibodies specific to different intermediate filament proteins revealed that VIP54 largely co-distributes with vimentin. In contrast to known intermediate filament proteins, VIP54 is predicted to contain approximately 50% of helical segments, but no extended coiled-coil regions. The possible involvement of this novel protein in interactions between intermediate filaments and late endosomal compartments is discussed.
de Bernard
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Centro CNR Biomembrane and Dipartimento di Scienze Biomediche, Università di Padova, Via G.Colombo 3, 35121 Padova, Italy. marina@civ.bio.unipd.it
Moschioni
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Napolitani
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Rappuoli
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Montecucco
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D000595:Amino Acid Sequence; D000818:Animals; D001253:Astrocytes / Q000737:chemistry; D001426:Bacterial Proteins / Q000378:metabolism*; D001427:Bacterial Toxins / Q000378:metabolism*; D002460:Cell Line; D003603:Cytotoxins / Q000378:metabolism; D004285:Dogs; D006367:HeLa Cells; D016480:Helicobacter pylori / Q000378:metabolism*; D006801:Humans; D007381:Intermediate Filament Proteins / Q000276:immunology / Q000302:isolation & purification* / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009447:Neuroblastoma / Q000737:chemistry; D009474:Neurons / Q000737:chemistry; D014407:Tumor Cells, Cultured; D014617:Vacuoles / Q000378:metabolism; D014746:Vimentin / Q000302:isolation & purification
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D003603:Cytotoxins; D007381:Intermediate Filament Proteins; C404157:VIP54 protein, Helicobacter pylori; C074689:VacA protein, Helicobacter pylori; D014746:Vimentin