Phosphorylation by Protein Kinase A Inhibits Nuclear Import of 5-Lipoxygenase
| Autor: | Sandra M. Jones, Nicolas Flamand, Ming Luo, David M. Aronoff, Thomas G. Brock, Marc Peters-Golden |
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| Rok vydání: | 2005 |
| Předmět: |
Cytoplasm
Recombinant Fusion Proteins Green Fluorescent Proteins 8-Bromo Cyclic Adenosine Monophosphate Gene Expression Glutamic Acid Mitogen-activated protein kinase kinase Transfection p38 Mitogen-Activated Protein Kinases Biochemistry Dinoprostone MAP2K7 Mice Structure-Activity Relationship Cyclic AMP Serine Animals ASK1 Protein phosphorylation Phosphorylation Protein kinase A Molecular Biology Cell Nucleus Alanine Arachidonate 5-Lipoxygenase Binding Sites biology Cyclin-dependent kinase 2 Biological Transport Cell Biology Autophagy-related protein 13 Cyclic AMP-Dependent Protein Kinases Cell biology Kinetics Mutagenesis Site-Directed NIH 3T3 Cells biology.protein cGMP-dependent protein kinase |
| Zdroj: | Journal of Biological Chemistry. 280:40609-40616 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.m507045200 |
| Popis: | The enzyme 5-lipoxygenase initiates the synthesis of leukotrienes from arachidonic acid. Protein kinase A phosphorylates 5-lipoxygenase on Ser(523), and this reduces its activity. We report here that phosphorylation of Ser(523) also shifts the subcellular distribution of 5-lipoxygenase from the nucleus to the cytoplasm. Phosphorylation and redistribution of 5-lipoxygenase could be produced by overexpression of the protein kinase A catalytic subunit alpha, by pharmacological activators of protein kinase A, and by prostaglandin E(2). Mimicking phosphorylation by replacing Ser(523) with glutamic acid caused cytoplasmic localization; replacement of Ser(523) with alanine prevented phosphorylation and redistribution in response to protein kinase A activation. Because Ser(523) is positioned within the nuclear localization sequence-518 of 5-lipoxygenase, the ability of protein kinase A to phosphorylate and alter the localization of green fluorescent protein fused to the nuclear localization sequence-518 peptide was also tested. Site-directed replacement of Ser(523) with glutamic acid within the peptide impaired nuclear accumulation; overexpression of the protein kinase A catalytic subunit alpha and pharmacological activation of protein kinase caused phosphorylation of the fusion protein at Ser(523), and the phosphorylated protein was found chiefly in the cytoplasm. Taken together, these results indicate that phosphorylation of Ser(523) inhibits the nuclear import function of a nuclear localization sequence, resulting in the accumulation of 5-lipoxygenase enzyme in the cytoplasm. As cytoplasmic localization can be associated with reduced leukotriene synthetic capacity, phosphorylation of Ser(523) serves to inhibit leukotriene production by both impairing catalytic activity and by placing the enzyme in a site that is unfavorable for action. |
| Databáze: | OpenAIRE |
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