title: Regulation of nuclear factor of activated T cells by phosphotyrosyl-specific phosphatase activity: a positive effect on HIV-1 long terminal repeat-driven transcription and a possible implication of SHP-1.
abstract: Although protein tyrosine phosphatase (PTP) inhibitors used in combination with other stimuli can induce interleukin 2 (IL-2) production in T cells, a direct implication of nuclear factor of activated T cells (NFAT) has not yet been demonstrated. This study reports that exposure of leukemic T cells and human peripheral blood mononuclear cells to bis-peroxovanadium (bpV) PTP inhibitors markedly induce activation and nuclear translocation of NFAT. NFAT activation by bpV was inhibited by the immunosuppressive drugs FK506 and cyclosporin A, as well as by a specific peptide inhibitor of NFAT activation. Mobility shift assays showed specific induction of the NFAT1 member by bpV molecules. The bpV-mediated NFAT activation was observed to be important for the up-regulation of the human immunodeficiency virus 1 (HIV-1) long terminal repeat (LTR) and the IL-2 promoter; NFAT1 was demonstrated to be particularly important in bpV-dependent positive action on HIV-1 LTR transcription. The active participation of p56(lck), ZAP-70, p21(ras), and calcium in the bpV-mediated signaling cascade leading to NFAT activation was confirmed, using deficient cell lines and dominant-negative mutants. Finally, overexpression of wild-type SHP-1 resulted in a greatly diminished activation of NFAT by bpV, suggesting an involvement of SHP-1 in the regulation of NFAT activation. These data were confirmed by constitutive NFAT translocation observed in Jurkat cells stably expressing a dominant-negative version of SHP-1. The study proposes that PTP activity attenuates constitutive kinase activities that otherwise would lead to constant NFAT activation and that this activation is participating in HIV-1 LTR stimulation by PTP inhibition.
authors: Centre de Recherche en Infectiologie, Centre Hospitalier Universitaire de Québec, Pavillon CHUL, Canada.
authors: J F
authors: JF
authors: Fortin
authors: B
authors: B
authors: Barbeau
authors: G A
authors: GA
authors: Robichaud
authors: M E
authors: ME
authors: Paré
authors: A M
authors: AM
authors: Lemieux
authors: M J
authors: MJ
authors: Tremblay
mesh_terms: D021581:Active Transport, Cell Nucleus; D000328:Adult; D016572:Cyclosporine / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D016325:HIV Long Terminal Repeat / Q000502:physiology*; D015497:HIV-1 / Q000502:physiology*; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology; D007375:Interleukin-1 / Q000235:genetics; D007376:Interleukin-2 / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins; D015759:Ionomycin / Q000494:pharmacology; D019169:Jurkat Cells / Q000187:drug effects / Q000378:metabolism; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / Q000172:deficiency / Q000502:physiology; D016328:NF-kappa B / Q000502:physiology; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D009942:Organometallic Compounds / Q000494:pharmacology; D010835:Phytohemagglutinins / Q000494:pharmacology; D011401:Promoter Regions, Genetic / Q000187:drug effects; D021381:Protein Transport; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors / Q000502:physiology*; D011505:Protein-Tyrosine Kinases / Q000502:physiology; D011948:Receptors, Antigen, T-Cell / Q000502:physiology; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000494:pharmacology; D016559:Tacrolimus / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014157:Transcription Factors / Q000502:physiology*; D014158:Transcription, Genetic / Q000187:drug effects*; D051746:ZAP-70 Protein-Tyrosine Kinase
chemical_list: D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D007166:Immunosuppressive Agents; D007375:Interleukin-1; D007376:Interleukin-2; D047908:Intracellular Signaling Peptides and Proteins; D016328:NF-kappa B; D050778:NFATC Transcription Factors; C494006:NFATC2 protein, human; D009687:Nuclear Proteins; D009942:Organometallic Compounds; D010835:Phytohemagglutinins; D011948:Receptors, Antigen, T-Cell; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors; C119540:oxodiperoxo(pyridine-2-carboxylate)vanadate(V); D015759:Ionomycin; D016572:Cyclosporine; D011505:Protein-Tyrosine Kinases; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D051746:ZAP-70 Protein-Tyrosine Kinase; C497261:ZAP70 protein, human; C509249:PTPN6 protein, human; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; D013755:Tetradecanoylphorbol Acetate; D016559:Tacrolimus