Nuclear translocation of extracellular superoxide dismutase

Tomomi Ookawara, Takako Kizaki, Eiji Takayama, Nobuo Imazeki, Osamu Matsubara, Yoshitaka Ikeda, Keiichiro Suzuki, Li Li Ji, Takushi Tadakuma, Naoyuki Taniguchi, Hideki Ohno

Research output: Contribution to journalArticlepeer-review

68 Scopus citations


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 languageEnglish (US)
Pages (from-to)54-61
Number of pages8
JournalBiochemical and Biophysical Research Communications
Issue number1
StatePublished - 2002
Externally publishedYes


  • Extracellular superoxide dismutase
  • Heparin binding domain
  • Nuclear localization signal
  • ROS
  • Secretion


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