title: The mitochondrial protein targeting suppressor (mts1) mutation maps to the mRNA-binding domain of Npl3p and affects translation on cytoplasmic polysomes.
abstract: In all eukaryotic organisms, messenger RNA (mRNA) is synthesized in the nucleus and then exported to the cytoplasm for translation. The export reaction requires the concerted action of a large number of protein components, including a set of shuttle proteins that can exit and re-enter the nucleus through the nuclear pore complex. Here, we show that, in Saccharomyces cerevisiae, the shuttle protein Npl3p leaves the nuclear pore complex entirely and continues to function in the cytoplasm. A mutation at position 219 in its RNA-binding domain leaves Npl3p lingering in the cytoplasm associated with polysomes. Yeast cells expressing the mutant Npl3(L-219S) protein show alterations in mRNA stability that can affect protein synthesis. As a result, defects in nascent polypeptide targeting to subcellular compartments such as the mitochondria are also suppressed.
authors.affiliation: Department of Biochemistry, La Trobe University, Bundoora 3083, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Gratzer
authors.forename: T
authors.initials: T
authors.lastname: Beilharz
authors.forename: T
authors.initials: T
authors.lastname: Beddoe
authors.forename: M F
authors.initials: MF
authors.lastname: Henry
authors.forename: T
authors.initials: T
authors.lastname: Lithgow
mesh_terms: D001665:Binding Sites; D001692:Biological Transport; D003593:Cytoplasm / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism*; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism*; D014176:Protein Biosynthesis; D020871:RNA Stability; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins
chemical_list: D005656:Fungal Proteins; C077734:NPL3 protein, S cerevisiae; D009687:Nuclear Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins