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.
Mesh Terms:
Amino Acid Sequence, Animals, Base Sequence, Biological Transport, Active, Carrier Proteins, Cytoplasm, DNA Primers, Fatty Acids, Unsaturated, Female, Fluorescent Antibody Technique, Indirect, Humans, Karyopherins, Microscopy, Immunoelectron, Nuclear Envelope, Oocytes, Peptide Initiation Factors, RNA-Binding Proteins, Receptors, Cytoplasmic and Nuclear, Recombinant Fusion Proteins, Xenopus laevis
J. Cell. Sci.
Date: Jul. 01, 1999
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