title: Action of diphtheria toxin does not depend on the induction of large, stable pores across biological membranes.
abstract: Vero cells exposed to diphtheria toxin at pH 4.5 leak monovalent cations but not amino acids or phosphorylated metabolites; affected cells do not take up trypan blue. Monovalent cation leakage is inhibited by 1 mM Cd2+, but not by 1 mM Zn2+ or Ca2+. Cd2+ blocks calcein leakage from liposomes and closes diphtheria toxin-induced channels in lipid bilayers. It is concluded that translocation of the A fragment of diphtheria toxin across biological membranes does not depend on the formation of large stable pores, but that small Cd2(+)-sensitive pores may play a role.
authors.affiliation: Department of Cellular and Molecular Sciences, St. George's Hospital Medical School, London, England.
authors.forename: G M
authors.initials: GM
authors.lastname: Alder
authors.forename: C L
authors.initials: CL
authors.lastname: Bashford
authors.forename: C A
authors.initials: CA
authors.lastname: Pasternak
mesh_terms: D000818:Animals; D002104:Cadmium / Q000494:pharmacology; D002462:Cell Membrane / Q000378:metabolism*; D003603:Cytotoxins / Q000494:pharmacology; D004167:Diphtheria Toxin / Q000494:pharmacology*; D005452:Fluoresceins / Q000378:metabolism; D007700:Kinetics; D008051:Lipid Bilayers / Q000378:metabolism; D008081:Liposomes / Q000378:metabolism*; D010539:Permeability; D011188:Potassium / Q000378:metabolism; D014176:Protein Biosynthesis; D012964:Sodium / Q000378:metabolism; D014709:Vero Cells
chemical_list: D003603:Cytotoxins; D004167:Diphtheria Toxin; D005452:Fluoresceins; D008051:Lipid Bilayers; D008081:Liposomes; D002104:Cadmium; D012964:Sodium; D011188:Potassium; C007740:fluorexon