title: The MKK6/p38 mitogen-activated protein kinase pathway is capable of inducing SOCS3 gene expression and inhibits IL-6-induced transcription.
abstract: In this study we show that activation of p38MAPK by IL-6 acts as an inhibitory signal on IL-6-mediated activation of STAT and the alpha2-macroglobulin promoter. We analyzed the role of MKK6/p38MAPK for IL-6 signal transduction and transcriptional activation of the suppressor of cytokine signaling (SOCS) 3 promoter. Pretreatment of cells with the p38MAPK-specific inhibitor SB202190 downregulates the induction of SOCS3-mRNA expression by IL-6. Accordingly, overexpression of a constitutively active MKK6 in HepG2 cells enhanced basal activity or IL-6-induced transcriptional activation of a SOCS3 promoter reporter construct, whereas overexpression of a dominant negative mutant of MKK6 downregulated the IL-6-mediated activation of the SOCS3 promoter. These data indicate that p38MAPK-activation is crucial for IL-6-induced SOCS3 expression and downregulation of IL-6-mediated gene induction.
authors.affiliation: Klinik für Gastroenterologie, Hepatologie und Infektiologie, Medizinische Klinik der Heinrich-Heine Universität, Düsseldorf, Germany.
authors.forename: J G
authors.initials: JG
authors.lastname: Bode
authors.forename: S
authors.initials: S
authors.lastname: Ludwig
authors.forename: C A
authors.initials: CA
authors.lastname: Freitas
authors.forename: F
authors.initials: F
authors.lastname: Schaper
authors.forename: M
authors.initials: M
authors.lastname: Ruhl
authors.forename: S
authors.initials: S
authors.lastname: Melmed
authors.forename: P C
authors.initials: PC
authors.lastname: Heinrich
authors.forename: D
authors.initials: D
authors.lastname: Häussinger
mesh_terms: D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D006528:Carcinoma, Hepatocellular; D004268:DNA-Binding Proteins / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D015850:Interleukin-6 / Q000378:metabolism* / Q000494:pharmacology; D048669:MAP Kinase Kinase 6; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011506:Proteins / Q000235:genetics* / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology; D012097:Repressor Proteins; D050794:STAT1 Transcription Factor; D050796:STAT3 Transcription Factor; D015398:Signal Transduction; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D007093:Imidazoles; D015850:Interleukin-6; D011506:Proteins; D011725:Pyridines; D012097:Repressor Proteins; C106644:SOCS3 protein, human; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048669:MAP Kinase Kinase 6; C482566:MAP2K6 protein, human; C090942:4-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)imidazole