title: mTOR regulates the nucleoplasmic diffusion of Xrn2 under conditions of heat stress.
abstract: Stress induces various responses, including translational suppression and tRNA degradation in mammals. Previously, we showed that heat stress induces degradation of initiator tRNA(Met) (iMet) through 5'-3' exoribonuclease Xrn1 and Xrn2, respectively. In addition, we found that rapamycin inhibits the degradation of iMet under heat stress conditions. Here, we report that the mammalian target of rapamycin (mTOR) regulates the diffusion of Xrn2 from the nucleolus to the nucleoplasm, facilitating the degradation of iMet under conditions of heat stress. Our results suggest a mechanism of translational suppression through mTOR-regulated iMet degradation in mammalian cells.
authors.affiliation: Department of Biotechnology, Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan; Radioisotope Center, The University of Tokyo, Tokyo, Japan. Electronic address: k_watanabe@okayama-u.ac.jp.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Watanabe
authors.affiliation: Radioisotope Center, The University of Tokyo, Tokyo, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Ijiri
authors.affiliation: Department of Biotechnology, Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Ohtsuki
mesh_terms: D002466:Cell Nucleolus / Q000378:metabolism*; D005095:Exoribonucleases / Q000378:metabolism*; D005786:Gene Expression Regulation; D006367:HeLa Cells; D018869:Heat-Shock Response; D006801:Humans; D014176:Protein Biosynthesis; D021381:Protein Transport; D020871:RNA Stability; D012358:RNA, Transfer, Met / Q000235:genetics / Q000378:metabolism*; D058570:TOR Serine-Threonine Kinases / Q000502:physiology*
chemical_list: D012358:RNA, Transfer, Met; C546842:MTOR protein, human; D058570:TOR Serine-Threonine Kinases; D005095:Exoribonucleases; C120903:XRN2 protein, human
keywords: Heat stress; Mammalian target of rapamycin; Xrn2; tRNA degradation