title: Regulation of tRNA bidirectional nuclear-cytoplasmic trafficking in Saccharomyces cerevisiae.
abstract: tRNAs in yeast and vertebrate cells move bidirectionally and reversibly between the nucleus and the cytoplasm. We investigated roles of members of the beta-importin family in tRNA subcellular dynamics. Retrograde import of tRNA into the nucleus is dependent, directly or indirectly, upon Mtr10. tRNA nuclear export utilizes at least two members of the beta-importin family. The beta-importins involved in nuclear export have shared and exclusive functions. Los1 functions in both the tRNA primary export and the tRNA reexport processes. Msn5 is unable to export tRNAs in the primary round of export if the tRNAs are encoded by intron-containing genes, and for these tRNAs Msn5 functions primarily in their reexport to the cytoplasm. The data support a model in which tRNA retrograde import to the nucleus is a constitutive process; in contrast, reexport of the imported tRNAs back to the cytoplasm is regulated by the availability of nutrients to cells and by tRNA aminoacylation in the nucleus. Finally, we implicate Tef1, the yeast orthologue of translation elongation factor eEF1A, in the tRNA reexport process and show that its subcellular distribution between the nucleus and cytoplasm is dependent upon Mtr10 and Msn5.
authors.affiliation: Department of Molecular Genetics, Graduate Program in Molecular, Cellular, and Developmental Biology, Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
authors.forename: Athulaprabha
authors.initials: A
authors.lastname: Murthi
authors.forename: Hussam H
authors.initials: HH
authors.lastname: Shaheen
authors.forename: Hsiao-Yun
authors.initials: HY
authors.lastname: Huang
authors.forename: Melanie A
authors.initials: MA
authors.lastname: Preston
authors.forename: Tsung-Po
authors.initials: TP
authors.lastname: Lai
authors.forename: Eric M
authors.initials: EM
authors.lastname: Phizicky
authors.forename: Anita K
authors.initials: AK
authors.lastname: Hopper
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000502:physiology*; D000818:Animals; D017404:In Situ Hybridization, Fluorescence; D028884:Karyopherins / Q000235:genetics / Q000378:metabolism; D028861:Nuclear Pore Complex Proteins / Q000235:genetics / Q000378:metabolism; D029543:Nucleocytoplasmic Transport Proteins / Q000235:genetics / Q000378:metabolism; D020648:Peptide Elongation Factor 1 / Q000235:genetics / Q000378:metabolism; D012343:RNA, Transfer / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D028961:beta Karyopherins / Q000235:genetics / Q000378:metabolism*
chemical_list: D028884:Karyopherins; C408090:Los1 protein, S cerevisiae; C401306:MSN5 protein, S cerevisiae; C110033:MTR10 protein, S cerevisiae; D028861:Nuclear Pore Complex Proteins; D029543:Nucleocytoplasmic Transport Proteins; D020648:Peptide Elongation Factor 1; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; C410826:TEF1 protein, S cerevisiae; D028961:beta Karyopherins; D012343:RNA, Transfer