title: Tumor necrosis factor alpha stimulates AP-1 activity through prolonged activation of the c-Jun kinase.
abstract: Tumor necrosis factor alpha (TNF alpha) has multiple biological functions including the prolonged activation of the collagenase and c-jun genes, which are regulated via their AP-1 binding sites. We show that incubating human fibroblasts with TNF alpha induces prolonged activation of JNK, the c-Jun kinase, which phosphorylates the transactivation domain of c-Jun. Furthermore, an immune complex kinase assay specifically demonstrates that TNF alpha stimulates the activity of JNK1, the recently described predominant form of JNK. TNF alpha also produces a small and transient increase in extracellular signal-regulated kinase (ERK) activity and no measured increase in Raf-1 kinase activity. On the other hand, epidermal growth factor causes a prolonged activation of Raf-1 kinase and ERK activity and a smaller, more transient activation of JNK, whereas the phorbol ester phorbol 12-myristate 13-acetate causes a small stimulation of Raf-1 kinase and a pronounced stimulation of ERK activity. The activation of JNK by TNF alpha does not correlate with Raf-1 or ERK activity. The kinetics of Raf-1, ERK, and JNK induction by epidermal growth factor, phorbol 12-myristate 13-acetate, or TNF alpha indicate distinct mechanisms of activation in human fibroblasts.
authors.affiliation: Department of Medicine, University of North Carolina, Chapel Hill 27599.
authors.forename: J K
authors.initials: JK
authors.lastname: Westwick
authors.forename: C
authors.initials: C
authors.lastname: Weitzel
authors.forename: A
authors.initials: A
authors.lastname: Minden
authors.forename: M
authors.initials: M
authors.lastname: Karin
authors.forename: D A
authors.initials: DA
authors.lastname: Brenner
mesh_terms: D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000096:biosynthesis; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D004789:Enzyme Activation; D006801:Humans; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism*; D019908:Proto-Oncogene Proteins c-raf; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D011518:Proto-Oncogene Proteins; D016755:Proto-Oncogene Proteins c-jun; D018808:Transcription Factor AP-1; D014409:Tumor Necrosis Factor-alpha; D004247:DNA; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D019908:Proto-Oncogene Proteins c-raf; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D013755:Tetradecanoylphorbol Acetate