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

AUTOR(ES)

Lipowsky, Gerd

FONTE

Oxford University Press

RESUMO

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.

Documentos Relacionados

• Exportin 7 defines a novel general nuclear export pathway
• Importin 13: a novel mediator of nuclear import and export
• Exportin 6: a novel nuclear export receptor that is specific for profilin·actin complexes
• Exportin 1 Mediates Nuclear Export of the Kinetoplastid Spliced Leader RNA
• Exportin-5-mediated nuclear export of eukaryotic elongation factor 1A and tRNA