title: Delta endotoxin inhibits Rb+ uptake, lowers cytoplasmic pH and inhibits a K+-ATPase in Manduca sexta CHE cells.
abstract: Delta endotoxin, a 68 kilodalton protein isolated from Bacillus thuringiensis spp. Kurstaki, is a potent entomocidal agent that alters a K+ current across midgut tissue of many phytophagous insects. This toxin completely inhibited the vanadate-sensitive 86Rb+ uptake and mimicked the vanadate-induced decrease in cytosolic pH in a cell line (CHE) originating from Manduca sexta embryonic tissue. The toxin also inhibited a K+-sensitive-ATPase in the plasma membranes isolated from these cells. Using the K+-sensitive-ATPase substrate p-nitrophenyl phosphate, delta endotoxin was found to have a Ki of 0.4 microM. These data suggest that the toxin inhibits a K+-ATPase responsible for 86Rb+ uptake in the CHE cells. The relationship between the toxin inhibition of K+-ATPase and toxin-altered K+ current is discussed.
authors.forename: L H
authors.initials: LH
authors.lastname: English
authors.forename: L C
authors.initials: LC
authors.lastname: Cantley
mesh_terms: D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors*; D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D001693:Biological Transport, Active / Q000187:drug effects; D027682:Cation Transport Proteins; D002460:Cell Line; D004731:Endotoxins / Q000494:pharmacology*; D006460:Hemolysin Proteins; D006863:Hydrogen-Ion Concentration; D007306:Insecticides / Q000494:pharmacology*; D007700:Kinetics; D007915:Lepidoptera / Q000378:metabolism*; D009036:Moths / Q000378:metabolism*; D010944:Plants; D011188:Potassium / Q000378:metabolism; D012413:Rubidium / Q000378:metabolism*; D014638:Vanadates; D014639:Vanadium / Q000494:pharmacology
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D027682:Cation Transport Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D007306:Insecticides; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D014639:Vanadium; D014638:Vanadates; D000251:Adenosine Triphosphatases; C022761:potassium transporting ATPase; D012413:Rubidium; D011188:Potassium