title: The tRNA aminoacylation co-factor Arc1p is excluded from the nucleus by an Xpo1p-dependent mechanism.
abstract: Arc1p, a yeast tRNA-binding protein, forms a complex with the aminoacyl-tRNA synthetases, methionyl tRNA synthetase (MetRS) and glutamyl tRNA synthetase (GluRS). Although this complex localizes normally in the cytoplasm, in the absence of Arc1p the two free synthetases are also found inside the nucleus. In this work, in order to localize free Arc1 we abolished complex assembly by deleting the appended domains from both MetRS and GluRS. Surprisingly, free Arc1p remained cytoplasmic even when fitted with a strong nuclear localization signal (NLS). However, NLS-Arc1p accumulated in the nucleus when Xpo1/Crm1, the export receptor for NES-containing cargo proteins, was mutated. Thus, the cytoplasmic location of Arc1p is maintained by Xpo1p-dependent nuclear export and Arc1p could act as an adapter in the nucleocytoplasmic trafficking of tRNA and/or the tRNA-aminoacylation machinery.
authors.affiliation: Biochemie-Zentrum Heidelberg, Im Neuenheimer Feld 328, D-69120 Heidelberg, Germany.
authors.forename: Kyriaki
authors.initials: K
authors.lastname: Galani
authors.forename: Ed
authors.initials: E
authors.lastname: Hurt
authors.forename: George
authors.initials: G
authors.lastname: Simos
mesh_terms: D002467:Cell Nucleus / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D005975:Glutamate-tRNA Ligase / Q000378:metabolism; D028884:Karyopherins / Q000378:metabolism*; D008718:Methionine-tRNA Ligase / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000378:metabolism; D021382:Protein Sorting Signals / Q000502:physiology; D021381:Protein Transport; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D046249:Transfer RNA Aminoacylation; D000097606:Exportin 1 Protein
chemical_list: D005975:Glutamate-tRNA Ligase; D028884:Karyopherins; D008718:Methionine-tRNA Ligase; D009687:Nuclear Proteins; D021382:Protein Sorting Signals; D016601:RNA-Binding Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D000097606:Exportin 1 Protein; C102145:ARC1 protein, S cerevisiae