title: The Hsp90 machinery facilitates the transport of diphtheria toxin into human cells.
abstract: Diphtheria toxin kills human cells because it delivers its enzyme domain DTA into their cytosol where it inhibits protein synthesis. After receptor-mediated uptake of the toxin, DTA translocates from acidic endosomes into the cytosol, which might be assisted by host cell factors. Here we investigated the role of Hsp90 and its co-chaperones during the uptake of native diphtheria toxin into human cells and identified the components of the Hsp90 machinery including Hsp90, Hsp70, Cyp40 and the FK506 binding proteins FKBP51 and FKBP52 as DTA binding partners. Moreover, pharmacological inhibition of the chaperone activity of Hsp90 and Hsp70 and of the peptidyl-prolyl cis/trans isomerase (PPIase) activity of Cyps and FKBPs protected cells from intoxication with diphtheria toxin and inhibited the pH-dependent trans-membrane transport of DTA into the cytosol. In conclusion, these host cell factors facilitate toxin uptake into human cells, which might lead to development of novel therapeutic strategies against diphtheria.
authors.affiliation: Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Ulm, Germany.
authors.forename: Manuel
authors.initials: M
authors.lastname: Schuster
authors.affiliation: Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Ulm, Germany.
authors.forename: Leonie
authors.initials: L
authors.lastname: Schnell
authors.affiliation: Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Ulm, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Feigl
authors.affiliation: Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Ulm, Germany.
authors.forename: Carina
authors.initials: C
authors.lastname: Birkhofer
authors.affiliation: Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Ulm, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Mohr
authors.affiliation: Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Ulm, Germany.
authors.forename: Maurice
authors.initials: M
authors.lastname: Roeder
authors.affiliation: Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Ulm, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Carle
authors.affiliation: Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Ulm, Germany.
authors.forename: Simon
authors.initials: S
authors.lastname: Langer
authors.affiliation: Munich Center for Integrated Protein Science and Department Chemistry, Technical University of Munich, Munich, Germany.
authors.forename: Franziska
authors.initials: F
authors.lastname: Tippel
authors.affiliation: Munich Center for Integrated Protein Science and Department Chemistry, Technical University of Munich, Munich, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Buchner
authors.affiliation: Max Planck Research Unit for Enzymology of Protein Folding Halle, Halle, Saale, Germany.
authors.forename: Gunter
authors.initials: G
authors.lastname: Fischer
authors.affiliation: Institute for Organic Chemistry and Biochemistry, Technical University Darmstadt, Darmstadt, Germany.|Department of Translational Research in Psychiatry, Max Planck Institute of Psychiatry, Munich, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Hausch
authors.affiliation: Institute of General Physiology, University of Ulm, Ulm, Germany.
authors.forename: Manfred
authors.identifier: http://orcid.org/0000-0002-4763-1104
authors.initials: M
authors.lastname: Frick
authors.affiliation: Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, 79104, Freiburg, Germany.
authors.forename: Carsten
authors.initials: C
authors.lastname: Schwan
authors.affiliation: Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, 79104, Freiburg, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Aktories
authors.affiliation: Institute for Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Saale, Germany.
authors.forename: Cordelia
authors.initials: C
authors.lastname: Schiene-Fischer
authors.affiliation: Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Ulm, Germany. holger.barth@uni-ulm.de.
authors.forename: Holger
authors.initials: H
authors.lastname: Barth
mesh_terms: D000818:Animals; D016466:CHO Cells; D002352:Carrier Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D003412:Cricetulus; D003600:Cytosol / Q000378:metabolism; D004167:Diphtheria Toxin / Q000378:metabolism* / Q000633:toxicity; D004789:Enzyme Activation / Q000187:drug effects; D018841:HSP90 Heat-Shock Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006367:HeLa Cells; D054884:Host-Pathogen Interactions; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008954:Models, Biological; D018832:Molecular Chaperones / Q000378:metabolism; D019696:Peptidylprolyl Isomerase / Q000378:metabolism; D011485:Protein Binding; D021381:Protein Transport; D059748:Proteolysis
chemical_list: D002352:Carrier Proteins; D004167:Diphtheria Toxin; D018841:HSP90 Heat-Shock Proteins; D018832:Molecular Chaperones; D019696:Peptidylprolyl Isomerase