Isolation and characterization of a T lymphocyte mutant defective in the protein kinase C signal transduction pathway.
The phorbol ester TPA is a potent protein kinase C (PKC) activator and a cofactor in the activation of the human Jurkat leukemic T cell line. We have studied the implication of the PKC signaling pathway in the process of T cell activation by generating TPA resistant mutants of Jurkat. These mutants were obtained by recovery of cells that survived a growth arrest induced by TPA. Several cellular phenomena dependent on TPA were dramatically altered in the mutated cells. The mutants were unable to form homoaggregates upon TPA stimulation. Moreover, they did not produce interleukin-2 after activation through engagement of the T cell receptor, in the presence of TPA. These results suggest that the PKC signaling pathway activated by TPA is defective in these cells. In an attempt to define and locate the defect present in the mutants, we have analysed the biochemical properties of PKC, the cellular receptor of TPA. The increase in kinase activity and the translocation of the enzyme to the plasma membrane after stimulation by TPA appeared to be normal in the mutants. We hypothesize that a metabolic step, critical for the completion of T cell activation, distinct from protein kinase C, is impaired in the mutant cells.
Unité 210, Institut National de la Santé et de la Recherche Médicale, Faculté de Médecine, Nice, France.
J F
JF
Peyron
J F
JF
Tanti
M
M
Limouse
D
D
Farahifar
P
P
Auberger
M
M
Fehlmann
D015703:Antigens, CD / Q000096:biosynthesis; D001692:Biological Transport; D002449:Cell Aggregation; D002852:Chromatography, Ion Exchange; D003600:Cytosol / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis; D015458:Leukemia, T-Cell; D008213:Lymphocyte Activation / Q000187:drug effects / Q000502:physiology*; D016296:Mutagenesis; D010766:Phosphorylation; D011493:Protein Kinase C / Q000493:pharmacokinetics / Q000502:physiology*; D038601:Ribosomal Protein S6; D012269:Ribosomal Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D015703:Antigens, CD; D007376:Interleukin-2; D038601:Ribosomal Protein S6; D012269:Ribosomal Proteins; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate