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  • The EMBO Journal (2002) 21, 6216 - 6224
  • doi:10.1093/emboj/cdf620

Exportin-5-mediated nuclear export of eukaryotic elongation factor 1A and tRNA

Angelo Calado1,2,4, Nathalie Treichel1,4, Eva-Christina Müller3, Albrecht Otto3 and Ulrike Kutay1

  1. Swiss Federal Institute of Technology (ETH) Zürich, Institute of Biochemistry, HPM F11.1, CH-8093 Zürich, Switzerland
  2. Present address: Instituto de Bioquímica, Universidade de Lisboa, Av. Prof. Egas Moniz, P-1649-028, Lisboa, Portugal
  3. Max-Delbrück-Centrum, Robert-Rössle-Stras zlige 10, D-13122 Berlin-Buch, Germany
  4. A.Calado and N.Treichel contributed equally to this work

Correspondence to:

Ulrike Kutay, E-mail: ulrike.kutay@bc.biol.ethz.ch

Received 28 August 2002; Accepted 30 September 2002; Revised 25 September 2002

Transport of proteins and RNA into and out of the cell nucleus is mediated largely by a family of RanGTP-binding transport receptors. Export receptors (exportins) need to bind RanGTP for efficient loading of their export cargo. We have identified eukaryotic elongation factor 1A (eEF1A) and tRNA as RanGTP-dependent binding partners of exportin-5 (Exp5). Exp5 stimulates nuclear export of eEF1A when microinjected into the nucleus of Xenopus laevis oocytes. Surprisingly, the interaction between eEF1A and Exp5 is dependent on tRNA that can interact directly with Exp5 and, if aminoacylated, recruits eEF1A into the export complex. These data suggested to us that Exp5 might support tRNA export. Indeed, not only the canonical tRNA export receptor, exportin-t, but also Exp5 can drive nuclear export of tRNA. Taken together, we show that there exists an alternative tRNA export pathway which can be exploited to keep eEF1A out of the cell nucleus.

  • Keywords:

    • eEF1A,
    • export receptor,
    • exportin-5,
    • nucleo-cytoplasmic transport,
    • tRNA