Inhibition and activation of interleukin 2 synthesis by direct modification of guanosine triphosphate-binding proteins.
To investigate whether guanosine triphosphate-binding proteins (G proteins) are involved in T cell activation, tests were made of the effect of pertussis toxin, cholera toxin, guanosine 5'-(3-O-thio)-triphosphate, and fluoride ions on interleukin 2 (IL-2) synthesis in Jurkat cells. It was found: 1) that pertussis toxin interferes with the first pathway of T cell activation insofar as it can substitute for phytohemagglutinin or monoclonal antibodies directed against the CD3 surface proteins, suggesting that a G protein serves as transducer for signals via the T cell receptor-CD3 complex; and 2) that fluoride ions induce the release of diacylglycerol (DAG) from [3H] arachidonic acid or [3H]oleic acid-prelabeled cells. In [3H]inositol or 32P-prelabeled cells, the increase in DAG production was also found to be accompanied by a 280% increase of intracellular inositol phosphate (IP), without significant modification of IP2 and IP3. These results suggest that a G protein controls the activity of a phospholipase C in Jurkat cells that upon stimulation releases DAG but not IP3. Inasmuch as DAG, like the phorbol ester tetradecanoyl phorbol acetate, activates protein kinase C, it suggests that a G protein is also involved in the transduction of the second signal for lymphocyte activation. Fluoride ions were found to be as effective as tetradecanoyl phorbol acetate to stimulate IL-2 synthesis in Jurkat cells when used in combination with phytohemagglutinin. Finally, cholera toxin and guanosine 5'-(3-O-thio)-triphosphate were found to increase intracellular cyclic adenosine triphosphate and to inhibit IL-2 synthesis. All together these results suggest that several G proteins are involved in the transduction of the two signals necessary for T cell activation as well as in the negative regulation of IL-2 synthesis.
Aussel
C
C
Institut National de la Santé et de la Recherche Médicale U210, Faculté de Médecine (Pasteur), Nice, France.
Mary
D
D
Peyron
J F
JF
Pelassy
C
C
Ferrua
B
B
Fehlmann
M
M
D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology; D017252:CD3 Complex; D000001:Calcimycin / Q000494:pharmacology; D002460:Cell Line; D002772:Cholera Toxin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D004075:Diglycerides / Q000378:metabolism; D005459:Fluorides / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000502:physiology*; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D006801:Humans; D007295:Inositol Phosphates / Q000378:metabolism; D007376:Interleukin-2 / Q000096:biosynthesis*; D008213:Lymphocyte Activation / Q000187:drug effects*; D037342:Pertussis Toxin; D010835:Phytohemagglutinins / Q000494:pharmacology; D013601:T-Lymphocytes / Q000502:physiology*; D013873:Thionucleotides / Q000494:pharmacology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D004075:Diglycerides; D007295:Inositol Phosphates; D007376:Interleukin-2; D010835:Phytohemagglutinins; D013873:Thionucleotides; D010566:Virulence Factors, Bordetella; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D000001:Calcimycin; D006160:Guanosine Triphosphate; D002772:Cholera Toxin; D000242:Cyclic AMP; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D005459:Fluorides