Nuclear pore localization and nucleocytoplasmic transport of eIF-5A: evidence for direct interaction with the export receptor CRM1.
Eukaryotic initiation factor 5A (eIF-5A) is the only cellular protein known to contain the unusual amino acid hypusine. The exact in vivo function of eIF-5A, however, is to date unknown. The finding that eIF-5A is an essential cofactor of the human immunodeficiency virus type 1 (HIV-1) Rev RNA transport factor suggested that eIF-5A is part of a specific nuclear export pathway. In this study we used indirect immunofluorescence and immunogold electron microscopy to demonstrate that eIF-5A accumulates at nuclear pore-associated intranuclear filaments in mammalian cells and Xenopus oocytes. We are able to show that eIF-5A interacts with the general nuclear export receptor, CRM1. Furthermore, microinjection studies in somatic cells revealed that eIF-5A is transported from the nucleus to the cytoplasm, and that this nuclear export is blocked by leptomycin B. Our data demonstrate that eIF-5A is a nucleocytoplasmic shuttle protein.
Rosorius
O
O
Institute for Clinical and Molecular Virology, University Erlangen-Nürnberg, Schlossgarten 4, D-91054 Erlangen, Germany.
Reichart
B
B
Krätzer
F
F
Heger
P
P
Dabauvalle
M C
MC
Hauber
J
J
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001693:Biological Transport, Active / Q000187:drug effects; D002352:Carrier Proteins / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D066298:In Vitro Techniques; D028884:Karyopherins; D016253:Microscopy, Immunoelectron; D009685:Nuclear Envelope / Q000378:metabolism*; D009865:Oocytes / Q000378:metabolism; D010448:Peptide Initiation Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014982:Xenopus laevis; D000097574:Eukaryotic Translation Initiation Factor 5A; D000097606:Exportin 1 Protein
D002352:Carrier Proteins; D017931:DNA Primers; D005231:Fatty Acids, Unsaturated; D028884:Karyopherins; D010448:Peptide Initiation Factors; D016601:RNA-Binding Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D011993:Recombinant Fusion Proteins; D000097574:Eukaryotic Translation Initiation Factor 5A; D000097606:Exportin 1 Protein; C038753:leptomycin B