Nuclear localization of 5-lipoxygenase as a determinant of leukotriene B4 synthetic capacity
| Autor: | Marc Peters-Golden, Sandra M. Jones, Ming Luo, Thomas G. Brock |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
Leukotriene B4
Active Transport Cell Nucleus In Vitro Techniques Transfection chemistry.chemical_compound Mice medicine Animals Cell Nucleus Multidisciplinary Nucleoplasm Arachidonate 5-Lipoxygenase biology Cell-Free System Intracellular Membranes Biological Sciences Subcellular localization Recombinant Proteins Cell biology Enzyme Activation Cell nucleus Cytosol medicine.anatomical_structure chemistry Amino Acid Substitution Cytoplasm Arachidonate 5-lipoxygenase biology.protein Mutagenesis Site-Directed NIH 3T3 Cells Nuclear localization sequence Subcellular Fractions |
| Zdroj: | Proceedings of the National Academy of Sciences of the United States of America. 100(21) |
| ISSN: | 0027-8424 |
| Popis: | The enzyme 5-lipoxygenase (5-LO) initiates the synthesis of leukotrienes from arachidonic acid. In resting cells, 5-LO can accumulate in either the cytoplasm or the nucleoplasm and, upon cell stimulation, translocates to membranes to initiate leukotriene synthesis. Here, we used mutants of 5-LO with altered subcellular localization to assess the role that nuclear positioning plays in determining leukotriene B4(LTB4) synthesis. Mutation of either a nuclear localization sequence or a phosphorylation site reduced LTB4synthesis by 60%, in parallel with reduced nuclear localization of 5-LO. Mutation of both sites together or mutation of all three nuclear localization sequences on 5-LO inhibited LTB4synthesis by 90% and abolished nuclear localization. Reduced LTB4generation in mutants could not be attributed to differences in 5-LO amount, enzymatic activity, or membrane association. Instead, 5-LO within the nucleus acts at a different site, the nuclear envelope, than does cytosolic 5-LO, which acts at cytoplasmic and perinuclear membranes. The significance of this difference was suggested by evidence that exogenously derived arachidonic acid colocalized with activated nuclear 5-LO. These results unequivocally demonstrate that the positioning of 5-LO within the nucleus of resting cells is a powerful determinant of the capacity to generate LTB4upon subsequent activation. |
| Databáze: | OpenAIRE |
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