Cholera toxin inhibits the T-cell antigen receptor-mediated increases in inositol trisphosphate and cytoplasmic free calcium.
The addition of monoclonal antibodies to the antigen receptor complex on the malignant human T-cell line Jurkat generates increases in inositol trisphosphate and in the concentration of cytoplasmic free calcium. Exposure of Jurkat cells to cholera toxin for 3 hr inhibited these receptor-mediated events and led to a selective, partial loss of the antigen receptor complex from the cellular surface. None of the effects of cholera toxin on the antigen receptor complex were mimicked by the B subunit of cholera toxin or by increasing intracellular cAMP levels with either forskolin or 8-bromo cAMP. These results suggest that a cholera toxin substrate can regulate signal transduction by the T-cell antigen receptor.
D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D000911:Antibodies, Monoclonal; D002118:Calcium / Q000502:physiology*; D002460:Cell Line; D002772:Cholera Toxin / Q000494:pharmacology*; D000242:Cyclic AMP / Q000502:physiology; D003593:Cytoplasm / Q000502:physiology; D019204:GTP-Binding Proteins / Q000378:metabolism; D006801:Humans; D007295:Inositol Phosphates / Q000502:physiology*; D007700:Kinetics; D011948:Receptors, Antigen, T-Cell / Q000502:physiology*; D013403:Sugar Phosphates / Q000502:physiology*; D013601:T-Lymphocytes / Q000276:immunology / Q000502:physiology*
D000911:Antibodies, Monoclonal; D007295:Inositol Phosphates; D011948:Receptors, Antigen, T-Cell; D013403:Sugar Phosphates; D000246:Adenosine Diphosphate Ribose; D002772:Cholera Toxin; D000242:Cyclic AMP; D019204:GTP-Binding Proteins; D002118:Calcium