title: Biological activity of a C-terminal fragment of Pasteurella multocida toxin.
abstract: The protein toxin of Pasteurella multocida PMT is a potent mitogen and activator of phospholipase Cbeta. In this study different toxin fragments were investigated. A C-terminal fragment encompassing amino acids 581 through 1285 (PMT581C) was constructed, which was inactive toward intact embryonic bovine lung (EBL) cells after addition to culture medium but caused reorganization of the actin cytoskeleton and rounding up of cells when introduced into the cells by electroporation. As the holotoxin, the toxin fragment PMT581C induced an increase in total inositol phosphate levels after introduction into the cell by electroporation. A C-terminal fragment shorter than PMT581C as well as N-terminal fragments were inactive. Exchange of cysteine-1165 for serine in the holotoxin resulted in a complete loss of the ability to increase inositol phosphate levels. Correspondingly, the mutated toxin fragment PMT581C.C1165S was inactive after cell introduction by electroporation, suggesting an essential role of Cys-1165 in the biological activity of the toxin.
authors.affiliation: Institut für Experimentelle und Klinische Pharmakologie und Toxikologie der Albert-Ludwigs-Universität Freiburg, D-79104 Freiburg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Busch
authors.forename: J
authors.initials: J
authors.lastname: Orth
authors.forename: N
authors.initials: N
authors.lastname: Djouder
authors.forename: K
authors.initials: K
authors.lastname: Aktories
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D001426:Bacterial Proteins; D001427:Bacterial Toxins / Q000737:chemistry* / Q000235:genetics / Q000633:toxicity*; D002417:Cattle; D002478:Cells, Cultured; D018274:Electroporation; D007295:Inositol Phosphates / Q000378:metabolism; D008168:Lung / Q000166:cytology / Q000196:embryology; D016979:Pasteurella multocida / Q000378:metabolism; D011994:Recombinant Proteins
chemical_list: D000199:Actins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D007295:Inositol Phosphates; C062258:Pasteurella multocida toxin; D011994:Recombinant Proteins