title: Hyperphosphorylation of calnexin, a chaperone protein, induced by Clostridium difficile cytotoxin.
abstract: Exposure of McCoy cultured cells to Clostridium difficile cytotoxin B or okadaic acid (OA), a potent phosphatase inhibitor, results in similar morphological changes. Using two-dimensional gel electrophoresis, we have detected a protein of approximately 77 kDa, with a pI of 4.5 (termed pp77) which is hyperphosphorylated in both cases. The level of phosphorylation of pp77 is increased by 293% and 35% after treatment with C. difficile cytotoxin B or OA, respectively. This protein was identified by microsequencing as calnexin, a protein which exhibits the characteristics of an endoplasmic reticulum (ER) chaperone.
authors.affiliation: Institut de Bactériologie, Université Louis Pasteur, Faculté de Medicine, Strasbourg, France.
authors.forename: V
authors.initials: V
authors.lastname: Schué
authors.forename: G A
authors.initials: GA
authors.lastname: Green
authors.forename: R
authors.initials: R
authors.lastname: Girardot
authors.forename: H
authors.initials: H
authors.lastname: Monteil
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D001427:Bacterial Toxins / Q000494:pharmacology*; D002135:Calcium-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D037281:Calnexin; D002460:Cell Line; D016360:Clostridioides difficile / Q000302:isolation & purification; D003603:Cytotoxins / Q000494:pharmacology; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D004768:Enterotoxins / Q000494:pharmacology; D004848:Epithelium; D004988:Ethers, Cyclic / Q000494:pharmacology; D005243:Feces / Q000382:microbiology; D006801:Humans; D008969:Molecular Sequence Data; D019319:Okadaic Acid; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification; D010750:Phosphoproteins / Q000302:isolation & purification / Q000378:metabolism; D010766:Phosphorylation; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors; D013583:Synovial Membrane
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D002135:Calcium-Binding Proteins; D003603:Cytotoxins; D004768:Enterotoxins; D004988:Ethers, Cyclic; D010446:Peptide Fragments; D010750:Phosphoproteins; C041348:tcdA protein, Clostridium difficile; C031815:toxB protein, Clostridium difficile; D037281:Calnexin; D019319:Okadaic Acid; D017027:Protein Tyrosine Phosphatases