Permeabilization of the plasma membrane by deletion mutants of diphtheria toxin.
Diphtheria toxin B-fragment binds to cell-surface receptors and facilitates translocation of the enzymatically active A-fragment to the cytosol. In this process the B-fragment inserts into the plasma membrane and induces formation of cation-selective channels. We examined the ability of a number of diphtheria toxin-derived molecules translated in vitro to permeabilize cells. Two proteins consisting of the whole B-fragment and small parts of the A-fragment, and one protein comprising most of the B-fragment alone, were more efficient than full-length toxin in permeabilizing the plasma membrane to monovalent cations. Two shorter B-fragment-derived proteins, with 3 and 10 kd N-terminal deletions, permeabilized the cells to sulfate and sucrose in addition to monovalent cations. The relationship between channel formation and toxin translocation is discussed.
Stenmark
H
H
Institute for Cancer Research, Norwegian Radium Hospital, Montebello, Oslo.
McGill
S
S
Olsnes
S
S
Sandvig
K
K
D000818:Animals; D002463:Cell Membrane Permeability; D004167:Diphtheria Toxin / Q000235:genetics / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007473:Ion Channels / Q000378:metabolism; D007700:Kinetics; D007739:L Cells; D009154:Mutation; D010446:Peptide Fragments / Q000378:metabolism; D014176:Protein Biosynthesis; D012964:Sodium / Q000378:metabolism; D014709:Vero Cells
D004167:Diphtheria Toxin; D007473:Ion Channels; D010446:Peptide Fragments; D012964:Sodium