Exportin 4: A mediator of a novel nuclear export pathway in higher eukaryotes

Gerd Lipowsky, F. Ralf Bischoff, Petra Schwarzmaier, Regine Kraft, Susanne Kostka, Enno Hartmann, Ulrike Kutay, Dirk Görlich*

*Corresponding author for this work
138 Citations (Scopus)


Transport receptors of the importin β superfamily account for many of the nuclear import and export events in eukaryotic cells. They mediate translocation through nuclear pore complexes, shuttle between nucleus and cytoplasm and co-operate with the RanGTPase system to regulate their interactions with cargo molecules in a compartment-specific manner. We used affinity chromatography on immobilized RanGTP to isolate further candidate nuclear transport receptors and thereby identified exportin 4 as the most distant member of the importin β family so far. Exportin 4 appears to be conserved amongst higher eukaryotes, but lacks obvious orthologues in yeast. It mediates nuclear export of eIF-5A (eukaryotic translation initiation factor 5A) and possibly that of other cargoes. The export signal in eIF-5A appears to be complex and to involve the hypusine modification that is unique to eIF-5A. We discuss possible cellular roles for nuclear export of eIF-5A.

Original languageEnglish
JournalEMBO Journal
Issue number16
Pages (from-to)4362-4371
Number of pages10
Publication statusPublished - 15.08.2000


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