Extracellular signal-dependent nuclear import of STAT3 is mediated by various importin αs

Ryosuke Ushijima, Naoko Sakaguchi, Arihiro Kano, Atsushi Maruyama, Yoichi Miyamoto, Toshihiro Sekimoto, Yoshihiro Yoneda, Kenji Ogino, Taro Tachibana

Research output: Contribution to journalArticle

41 Citations (Scopus)

Abstract

The signal transducer and activator of transcription 3 (STAT3) is a transcription factor that is involved in a variety of biological functions. STAT3 is activated by cytokines and growth factors via the phosphorylation of a tyrosine residue, dimerization, and subsequent nuclear translocation. However, the mechanism of its nuclear translocation is unclear. A study of the cytokine-stimulated import of STAT3 into the nucleus is reported herein. An oncostatin M (OSM)-dependent nuclear import assay system was first established in living cells. Using this system, we demonstrated that the microinjection of the importin α5/NPI-1 mutant, an anti-importin β antibody, and the RanQ69L mutant inhibited the nuclear import of STAT3. Second, we showed that tyrosine-phosphorylated STAT3 associates, not only with importin α5/NPI-1 but also with other importin αs, as a result of OSM stimulation, as evidenced by a solution binding assay. These findings suggest that the extracellular signal-dependent nuclear transport of STAT3 is mediated by various importin αs, importin β, and Ran.

Original languageEnglish
Pages (from-to)880-886
Number of pages7
JournalBiochemical and Biophysical Research Communications
Volume330
Issue number3
DOIs
Publication statusPublished - May 13 2005
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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