title: Mechanism of the stress-induced collapse of the Ran distribution.
abstract: The small GTPase Ran plays a central role in several key nuclear functions, including nucleocytoplasmic transport, cell cycle progression, and assembly of the nuclear envelope. In a previous study, we showed that cellular stress induces the nuclear accumulation of importin alpha, and that this appears to be triggered by a collapse in the Ran gradient, leading to the down-regulation of classical nuclear transport. We report here that a decrease in stress-induced ATP is associated with an increase in cytoplasmic Ran levels. A luciferin-luciferase assay showed that cellular stress decreased the intracellular levels of ATP. Treatment of the cells with ATP-depleting agents altered the distribution of Ran. Furthermore, when exogenous ATP was introduced in oxidative stress-treated cells, a normal distribution of Ran was restored. In addition, a pull-down experiment with an importin beta1 variant that binds to RanGTP showed that oxidative stress was accompanied by a decrease in intracellular RanGTP levels. These findings indicate that the decrease in ATP levels induced by cellular stress causes a decrease in RanGTP levels and a collapse of Ran distribution.
authors.affiliation: Department of Frontier Biosciences, Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamada-oka, Suita, Osaka 565-0871, Japan.
authors.forename: Yoshinari
authors.initials: Y
authors.lastname: Yasuda
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Miyamoto
authors.forename: Takuya
authors.initials: T
authors.lastname: Saiwaki
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Yoneda
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000187:drug effects / Q000528:radiation effects; D000255:Adenosine Triphosphate / Q000378:metabolism / Q000494:pharmacology; D001081:Apyrase / Q000494:pharmacology; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000037:antagonists & inhibitors; D006367:HeLa Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D018384:Oxidative Stress / Q000502:physiology*; D012717:Sesquiterpenes / Q000494:pharmacology; D014162:Transfection; D014466:Ultraviolet Rays; D014909:Wheat Germ Agglutinins / Q000494:pharmacology; D028961:beta Karyopherins / Q000235:genetics / Q000378:metabolism; D020931:ran GTP-Binding Protein / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; C424166:KPNB1 protein, human; D012717:Sesquiterpenes; D014909:Wheat Germ Agglutinins; D028961:beta Karyopherins; C027285:heptelidic acid; D000255:Adenosine Triphosphate; D006861:Hydrogen Peroxide; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D001081:Apyrase; D020931:ran GTP-Binding Protein