Heat-shock stress activates a novel nuclear import pathway mediated by Hikeshi.
Cellular stresses significantly affect nuclear transport systems. Nuclear transport pathways mediated by importin β-family members, which are active under normal conditions, are downregulated. During thermal stress, a nuclear import pathway mediated by a novel carrier, which we named Hikeshi, becomes active. Hikeshi is not a member of the importin β family and mediates the nuclear import of Hsp70s. Unlike importin β family-mediated nuclear transport, the Hikeshi-mediated nuclear import of Hsp70s is not coupled to the GTPase cycle of the small GTPase Ran but rather is coupled with the ATPase cycle of Hsp70s. Hikeshi-mediated nuclear import is essential for the attenuation and reversal of the thermal stress response in human cells. The mechanism and functions of this newly identified nuclear import pathway will be discussed.
Cellular Dynamics Laboratory; RIKEN Advanced Science Institute; Wako, Saitama, Japan. nimamoto@riken.jp
Naoko
N
Imamoto
Shingo
S
Kose
D021581:Active Transport, Cell Nucleus; D002352:Carrier Proteins / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D018869:Heat-Shock Response; D006801:Humans; D011485:Protein Binding; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D020931:ran GTP-Binding Protein / Q000378:metabolism
D002352:Carrier Proteins; D018840:HSP70 Heat-Shock Proteins; D034741:RNA, Small Interfering; C572913:hikeshi protein, human; D020931:ran GTP-Binding Protein