title: Protein kinase C activity is required for aryl hydrocarbon receptor pathway-mediated signal transduction.
abstract: The role of protein kinase C (PKC) in the human aryl hydrocarbon receptor (hAhR) signal transduction pathway was examined in cell lines stably transfected with pGUDLUC6.1, in which luc+ is solely controlled by four dioxin-responsive elements (DREs). These cell lines, P5A11 and HG40/6, were derived from HeLa and HepG2 cells respectively. Simultaneous treatment of these cells with 2,3,7,8, -tetrachlorodibenzo-p-dioxin (TCDD) and phorbol-12-myristate-13-acetate (PMA) enhanced trans-activation of the reporter construct several-fold relative to cells treated with TCDD alone. PKC inhibitors block the PMA effect and hAhR-mediated signal transduction, demonstrating these processes require PKC activity. Examination of other independently generated, HeLa-derived cell lines stably transfected with pGUDLUC6.1 demonstrates the PMA effect in P5A11 cells is not a clonal artifact. Transient transfections indicate the PMA effect is not due to a luciferase message/gene product stabilization mechanism or stimulation of the basal transcription machinery. Examination of cytosolic preparations demonstrates PKC stimulation or inhibition does not alter hAhR and hAhR nuclear translocator protein levels or TCDD-induced down-regulation of hAhR levels. Similarly, examination of nuclear extracts indicated PKC stimulation or inhibition does not alter nuclear AhR levels or hAhR/hAhR nuclear translocator protein heterodimer DRE-binding activity as assessed by electrophoretic mobility shift assay. These results demonstrate a PKC-mediated event is required for the hAhR to form a functional transcriptional complex that leads to trans-activation and that the DRE is the minimal DNA element required for PMA to enhance AhR-mediated trans-activation.
authors.affiliation: Graduate Program in Biochemistry Cell and Molecular Biology, Department of Veterinary Science, The Pennsylvania State University, University Park 16802, USA.
authors.forename: W P
authors.initials: WP
authors.lastname: Long
authors.forename: M
authors.initials: M
authors.lastname: Pray-Grant
authors.forename: J C
authors.initials: JC
authors.lastname: Tsai
authors.forename: G H
authors.initials: GH
authors.lastname: Perdew
mesh_terms: D000470:Alkaloids; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator; D053119:Benzophenanthridines; D006528:Carcinoma, Hepatocellular; D003600:Cytosol / Q000378:metabolism; D004268:DNA-Binding Proteins; D019281:Dimerization; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005822:Genetic Vectors / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D008113:Liver Neoplasms; D008301:Maleimides / Q000494:pharmacology; D010617:Phenanthridines / Q000494:pharmacology; D000072317:Polychlorinated Dibenzodioxins / Q000378:metabolism / Q000494:pharmacology; D011485:Protein Binding; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018336:Receptors, Aryl Hydrocarbon / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects; D013755:Tetradecanoylphorbol Acetate / Q000031:analogs & derivatives / Q000494:pharmacology; D014157:Transcription Factors / Q000378:metabolism; D015533:Transcriptional Activation / Q000187:drug effects; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: C497396:ARNT protein, human; D000470:Alkaloids; D053119:Benzophenanthridines; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D007211:Indoles; D008301:Maleimides; D010617:Phenanthridines; D000072317:Polychlorinated Dibenzodioxins; D018336:Receptors, Aryl Hydrocarbon; D014157:Transcription Factors; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator; C016299:chelerythrine; D011493:Protein Kinase C; C088060:bisindolylmaleimide; D013755:Tetradecanoylphorbol Acetate