TY - JOUR
T1 - Extracellular signal-dependent nuclear import of STAT3 is mediated by various importin αs
AU - Ushijima, Ryosuke
AU - Sakaguchi, Naoko
AU - Kano, Arihiro
AU - Maruyama, Atsushi
AU - Miyamoto, Yoichi
AU - Sekimoto, Toshihiro
AU - Yoneda, Yoshihiro
AU - Ogino, Kenji
AU - Tachibana, Taro
PY - 2005/5/13
Y1 - 2005/5/13
N2 - 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.
AB - 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.
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U2 - 10.1016/j.bbrc.2005.03.063
DO - 10.1016/j.bbrc.2005.03.063
M3 - Article
C2 - 15809078
AN - SCOPUS:16244363060
VL - 330
SP - 880
EP - 886
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
SN - 0006-291X
IS - 3
ER -