1α,25-Dihydroxyvitamin D3 Stimulates Activator Protein 1 DNA-Binding Activity by a Phosphatidylinositol 3-Kinase/Ras/MEK/Extracellular Signal Regulated Kinase 1/2 and c-Jun N-Terminal Kinase 1-Dependent Increase in c-Fos, Fra1, and c-Jun Expression in Human Keratinocytes
| Autor: | Majken Westergaard, Knud Kragballe, Jeanette Henningsen, Karsten Kristiansen, Claus Johansen, Lars Iversen |
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| Rok vydání: | 2003 |
| Předmět: |
Adult
keratinocytes mitogen-activated protein kinase MAP Kinase Signaling System Proto-Oncogene Proteins c-jun Gene Expression MAP Kinase Kinase Kinase 1 Dermatology Protein Serine-Threonine Kinases Mitogen-activated protein kinase kinase Biochemistry Antibodies MAP2K7 Phosphatidylinositol 3-Kinases Calcitriol Humans ASK1 RNA Messenger c-Raf activator protein 1 Phosphorylation Molecular Biology Annexin A2 Cells Cultured Mitogen-Activated Protein Kinase 1 Mitogen-Activated Protein Kinase 3 MAP kinase kinase kinase biology Akt/PKB signaling pathway Cyclin-dependent kinase 2 JNK Mitogen-Activated Protein Kinases Cell Biology Molecular biology Cell biology 1α 25-dihydroxyvitamin D3 Transcription Factor AP-1 Calcium Channel Agonists ras Proteins biology.protein Cyclin-dependent kinase 9 Mitogen-Activated Protein Kinases Proto-Oncogene Proteins c-fos annexin II |
| Zdroj: | Aarhus University |
| ISSN: | 0022-202X |
| DOI: | 10.1046/j.1523-1747.2003.12095.x |
| Popis: | 1alpha,25-Dihydroxyvitamin D3 added to human keratinocytes increases differentiation through an activation of the transcription factor activator protein 1. We have previously reported that the 1alpha,25-dihydroxyvitamin D3-induced increase of activator protein 1 DNA binding activity is mediated by a protein kinase C-independent mechanism. The purpose of this study was to investigate further the mechanisms by which 1alpha,25-dihydroxyvitamin D3 modulates activator protein 1 DNA binding activity in cultured normal human keratinocytes. Western blotting experiments revealed that 1alpha,25-dihydroxyvitamin D3 caused a rapid and transient activation of the mitogen-activated protein kinases, extracellular signal regulated kinase 1/2 and c-Jun N-terminal kinase 1. 1alpha,25-Dihydroxyvitamin D3 also enhanced the expression of the activator protein 1 subunits, c-Fos, Fra1, and c-Jun as determined by northern and western blotting. The 1alpha,25-dihydroxyvitamin D3-induced activator protein 1 DNA binding activity was completely blocked by the MEK inhibitor PD 98059 indicating that the MEK/extracellular signal regulated kinase pathway is involved in the activation of activator protein 1. Transfection experiments showed that 1alpha,25-dihydroxyvitamin D3 also increased the activator protein 1-dependent transactivation, which was completely blocked by expression of a dominant negative Ras, suggesting that the 1alpha,25-dihydroxyvitamin D3-induced activator protein 1 activity involves Ras-dependent signaling. Furthermore, preincubation of the keratinocytes with the specific phosphatidylinositol 3-kinase inhibitors, Wortmannin and LY294002, demonstrated that the 1alpha,25-dihydroxyvitamin D3-induced activation of extracellular signal regulated kinase 1/2 and c-Jun N-terminal kinase 1 required phosphatidylinositol 3-kinase activity. Finally, preincubation of keratinocytes with a polyclonal antibody against the membrane receptor annexin II, blocked the 1alpha,25-dihydroxyvitamin D3-induced activation of extracellular signal regulated kinase 1/2 and c-Jun N-terminal kinase 1. Taken together, our results indicate that 1alpha,25-dihydroxyvitamin D3, via binding to the membrane receptor annexin II, induces activation of the phos-phatidylinositol 3-kinase/Ras/MEK/extracellular signal regulated kinase 1/2 and c-Jun N-terminal kinase 1 signal transduction pathway resulting in increased expression of c-Fos, Fra1, and c-Jun, and subsequently increased activator protein 1 DNA binding activity and gene transcription. |
| Databáze: | OpenAIRE |
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