Heat-shock induced nuclear retention and recycling inhibition of importin α

Maiko Furuta, Shingo Kose, Makiko Koike, Takeshi Shimi, Yasushi Hiraoka, Yoshihiro Yoneda, Tokuko Haraguchi, Naoko Imamoto*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

49 Scopus citations


Heat-shock induces a strong stress response and modifies all aspects of cellular physiology, which involves dynamic changes in the nucleocytoplasmic distributions of a variety of proteins. Many distinct nucleocyto-plasmic transport pathways exist in eukaryotic cells, but how a particular transport pathway is regulated under different cellular conditions remains elusive. The finding of this study indicate that conventional nuclear import, which is mediated by importin α/β, is down-regulated, while the nuclear import of 70 kD heat-shock cognate protein is up-regulated in heat-shock cells. Among the factors involved in the mediation of the conventional nuclear import, significant levels of importin α accumulate in the nucleus in response to heat-shock. An analysis of the behaviour of importin α with fluorescence recovery after photobleaching and fluorescence loss in photobleaching studies show that nuclear importin α becomes less mobile and its nucleo-cytoplasmic recycling is impaired in heat-shock cells. These data coincided well with biochemical and cytological studies. Our present data show that heat-shock induces the nuclear accumulation, nuclear retention, and recycling inhibition of importin α, resulting in the suppression of conventional nuclear import. This suggests a new regulatory mechanism for the adaptation of cells to environmental changes, such as heat-shock.

Original languageEnglish (US)
Pages (from-to)429-441
Number of pages13
JournalGenes to Cells
Issue number5
StatePublished - May 2004

ASJC Scopus subject areas

  • Genetics
  • Cell Biology


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