The nuclear pore component Nup358 promotes transportin-dependent nuclear import.
Nup358 (also known as RanBP2), a component of the cytoplasmic filaments of the nuclear pore complex, has been implicated in various nucleocytoplasmic transport pathways. Here, we identify Nup358 as an important factor for transportin-mediated nuclear import. Depletion of Nup358 resulted in a strong inhibition of nuclear import of the human immunodeficiency virus type 1 (HIV-1) Rev protein. HIV-1 Rev is an RNA-binding protein that is required for CRM1 (also known as exportin 1)-dependent nuclear export of unspliced or partially spliced viral RNA. We show that transportin is the major nuclear import receptor for HIV-1 Rev in HeLa cells. Overexpression of transportin strongly promoted nuclear import of HIV-1 Rev in Nup358-depleted cells, indicating that the import receptor becomes rate-limiting under these conditions. Importantly, the import rate of other transportin-dependent proteins was also significantly reduced in Nup358-depleted cells. Our data therefore suggest a general role for Nup358 in transportin-mediated nuclear import.
Hutten
Saskia
S
Department of Biochemistry I, Faculty of Medicine, Georg-August-University of Göttingen, 37073, Göttingen, Germany.
Wälde
Sarah
S
Spillner
Christiane
C
Hauber
Joachim
J
Kehlenbach
Ralph H
RH
D021581:Active Transport, Cell Nucleus; D006367:HeLa Cells; D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B / Q000378:metabolism; D034761:Heterogeneous-Nuclear Ribonucleoprotein Group M / Q000378:metabolism; D006801:Humans; D028884:Karyopherins / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism*; D022022:Nuclear Pore / Q000378:metabolism*; D028861:Nuclear Pore Complex Proteins / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014162:Transfection; D054321:rev Gene Products, Human Immunodeficiency Virus / Q000235:genetics / Q000378:metabolism*
D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D034761:Heterogeneous-Nuclear Ribonucleoprotein Group M; D028884:Karyopherins; D018832:Molecular Chaperones; D028861:Nuclear Pore Complex Proteins; D011993:Recombinant Fusion Proteins; C094493:ran-binding protein 2; D054321:rev Gene Products, Human Immunodeficiency Virus; C514860:rev protein, Human Immunodeficiency Virus-1