Phospho-eNOS Ser-114 in human mesenchymal stem cells: Constitutive phosphorylation, nuclear localization and upregulation during mitosis
| Autor: | Klara Brixius, Uwe Mehlhorn, F. Popken, Peter Staib, Wilhelm Bloch, Franz-Josef Klinz, Klaus Addicks, Stefan Arnhold, Robert H. G. Schwinger, Biren Desai, Timo Schinköthe, Annette Schmidt |
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| Rok vydání: | 2005 |
| Předmět: |
inorganic chemicals
Histology Nitric Oxide Synthase Type III Cell division Caveolin 1 Active Transport Cell Nucleus Mitosis macromolecular substances environment and public health Pathology and Forensic Medicine Phosphoserine Enos Humans Protein Isoforms Phosphorylation biology Endothelial Cells Colocalization Mesenchymal Stem Cells Cell Biology General Medicine Flow Cytometry biology.organism_classification Subcellular localization Molecular biology Cell Compartmentation Up-Regulation Nitric oxide synthase Protein Transport enzymes and coenzymes (carbohydrates) Cytosol Antigens Surface biology.protein bacteria |
| Zdroj: | European Journal of Cell Biology. 84:809-818 |
| ISSN: | 0171-9335 |
| Popis: | Activity of endothelial nitric oxide synthase (eNOS) is modulated by protein-protein interaction and phosphorylation at specific serine or threonine residues. Using immunofluorescence analysis we show here that proliferating mesenchymal stem cells (MSCs) derived from human bone marrow exhibit cytosolic and pronounced nuclear localization of eNOS. Examination of phosphorylated eNOS subspecies revealed that eNOS phosphorylated at Ser-114 is heavily enriched in the nucleus, whereas eNOS phosphorylated at Ser-1177 is localized at filamentous structures in the cytosol that are abundant in the perinuclear region. Phosphorylation of eNOS at Ser-114 but not at Ser-1177 was strongly increased in cells shortly before mitosis and decreased to normal level after completed cell division. Double immunofluorescence analysis revealed that subcellular localization of 8-hydroxyguanosine immunoreactivity was overlapping with eNOS phosphorylated at Ser-114 in human MSCs providing evidence that phosphorylation at this residue is linked to the generation of superoxide anions. As expected there was only a weak colocalization between eNOS phosphorylated at Ser-1177 and caveolin-1. Different from many other cell systems, human MSCs accumulate eNOS in the nucleus without an acute stimulus. eNOS constitutively phosphorylated at distinct amino acid residues is targeted to different subcellular compartments pointing to an important role of specific phosphorylation events in the life cycle of proliferating human MSCs. |
| Databáze: | OpenAIRE |
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