The mobile FG nucleoporin Nup98 is a cofactor for Crm1-dependent protein export.
Nup98 is a mobile nucleoporin that forms distinct dots in the nucleus, and, although a role for Nup98 in nuclear transport has been suggested, its precise function remains unclear. Here, we show that Nup98 plays an important role in Crm1-mediated nuclear protein export. Nuclear, but not cytoplasmic, dots of EGFP-tagged Nup98 disappeared rapidly after cell treatment with leptomycin B, a specific inhibitor of the nuclear export receptor, Crm1. Mutational analysis demonstrated that Nup98 physically and functionally interacts with Crm1 in a RanGTP-dependent manner through its N-terminal phenylalanine-glycine (FG) repeat region. Moreover, the activity of the Nup98-Crm1 complex was modulated by RanBP3, a known cofactor for Crm1-mediated nuclear export. Finally, cytoplasmic microinjection of anti-Nup98 inhibited the Crm1-dependent nuclear export of proteins, concomitant with the accumulation of anti-Nup98 in the nucleus. These results clearly demonstrate that Nup98 functions as a novel shuttling cofactor for Crm1-mediated nuclear export in conjunction with RanBP3.
Oka
Masahiro
M
Department of Biochemistry, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan.
Asally
Munehiro
M
Yasuda
Yoshinari
Y
Ogawa
Yutaka
Y
Tachibana
Taro
T
Yoneda
Yoshihiro
Y
D021581:Active Transport, Cell Nucleus / Q000502:physiology*; D000818:Animals; D002466:Cell Nucleolus / Q000378:metabolism; D004252:DNA Mutational Analysis; D003609:Dactinomycin / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D028884:Karyopherins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D041681:NIH 3T3 Cells; D028861:Nuclear Pore Complex Proteins / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D029543:Nucleocytoplasmic Transport Proteins / Q000235:genetics / Q000378:metabolism; D011500:Protein Synthesis Inhibitors / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020931:ran GTP-Binding Protein / Q000235:genetics / Q000378:metabolism; D000097606:Exportin 1 Protein
D003609:Dactinomycin; D028884:Karyopherins; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins; D029543:Nucleocytoplasmic Transport Proteins; D011500:Protein Synthesis Inhibitors; D018160:Receptors, Cytoplasmic and Nuclear; D011993:Recombinant Fusion Proteins; D020931:ran GTP-Binding Protein; D000097606:Exportin 1 Protein; C112820:RANBP3 protein, human; C093350:nuclear pore complex protein 98