Abstract
Histochemical examination of mouse tissues showed nuclear staining of extracellular superoxide dismutase (EC-SOD), and the nuclear translocation of EC-SOD was also confirmed in cultured cells that had been transfected with its gene, as shown by immunohistochemistry and Western blot analysis. The EC-SOD which was secreted into the medium was incorporated into 3T3-L1 cells and a significant fraction of the material taken up was localized in the nucleus. Site-directed mutagenesis indicated that the heparin-binding domain of EC-SOD functions as the nuclear localization signal. These results suggest that the mechanism of the nuclear transport of EC-SOD involves a series of N-terminal signal peptide- and C-terminal heparin-binding domain-dependent processes of secretion, re-uptake and the subsequent nuclear translocation. The findings herein provide support for the view that the role of EC-SOD is to protect the genome DNA from damage by reactive oxygen species and/or the transcriptional regulation of redox-sensitive gene expression.
Original language | English (US) |
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Pages (from-to) | 54-61 |
Number of pages | 8 |
Journal | Biochemical and Biophysical Research Communications |
Volume | 296 |
Issue number | 1 |
DOIs | |
State | Published - 2002 |
Externally published | Yes |
Keywords
- Extracellular superoxide dismutase
- Heparin binding domain
- Nuclear localization signal
- ROS
- Secretion