The Role of Nitric-oxide Synthase in the Regulation of UVB Light-induced Phosphorylation of the α Subunit of Eukaryotic Initiation Factor 2
| Autor: | Shiyong Wu, Wei Lu, Zhixin Miao, Hao Chen, Csaba F. László |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
endocrine system
Ultraviolet Rays Eukaryotic Initiation Factor-2 Protein Serine-Threonine Kinases Biology Biochemistry Cell Line Phosphorylation cascade Mice eIF-2 Kinase Animals Humans Enzyme Inhibitors Phosphorylation Protein kinase A Molecular Biology eIF2 EIF-2 kinase omega-N-Methylarginine Kinase Protein Synthesis Post-Translational Modification and Degradation Free Radical Scavengers Cell Biology Free radical scavenger Molecular biology Acetylcysteine Cell biology Oxidative Stress biology.protein Nitric Oxide Synthase Signal transduction |
| Zdroj: | Journal of Biological Chemistry. 284:24281-24288 |
| ISSN: | 0021-9258 |
| Popis: | UV light induces phosphorylation of the alpha subunit of the eukaryotic initiation factor 2 (eIF2alpha) and inhibits global protein synthesis. Both eIF2 kinases, protein kinase-like endoplasmic reticulum kinase (PERK) and general control of nonderepressible protein kinase 2 (GCN2), have been shown to phosphorylate eIF2alpha in response to UV irradiation. However, the roles of PERK and GCN2 in UV-induced eIF2alpha phosphorylation are controversial. The one or more upstream signaling pathways that lead to the activation of PERK or GCN2 remain unknown. In this report we provide data showing that both PERK and GCN2 contribute to UV-induced eIF2alpha phosphorylation in human keratinocyte (HaCaT) and mouse embryonic fibroblast cells. Reduction of expression of PERK or GCN2 by small interfering RNA decreases phosphorylation of eIF2alpha after UV irradiation. These data also show that nitric-oxide synthase (NOS)-mediated oxidative stress plays a role in regulation of eIF2alpha phosphorylation upon UV irradiation. Treating the cells with the broad NOS inhibitor N(G)-methyl-l-arginine, the free radical scavenger N-acetyl-l-cysteine, or the NOS substrate l-arginine partially inhibits UV-induced eIF2alpha phosphorylation. The results presented above led us to propose that NOS mediates UV-induced eIF2alpha phosphorylation by activation of both PERK and GCN2 via oxidative stress and l-arginine starvation signaling pathways. |
| Databáze: | OpenAIRE |
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