Arc1p is required for cytoplasmic confinement of synthetases and tRNA.
In yeast, Arc1p interacts with ScMetRS and ScGluRS and operates as a tRNA-Interacting Factor (tIF) in trans of these two synthetases. Its N-terminal domain (N-Arc1p) binds the two synthetases and its C-terminal domain is an EMAPII-like domain organized around an OB-fold-based tIF. ARC1 is not an essential gene but its deletion (arc1- cells) is accompanied by a growth retardation phenotype. Here, we show that expression of N-Arc1p or of C-Arc1p alone palliates the growth defect of arc1- cells, and that bacterial Trbp111 or human p43, two proteins containing EMAPII-like domains, also improve the growth of an arc1- strain. The synthetic lethality of an arc1-los1- strain can be complemented with either ARC1 or LOS1. Expression of N-Arc1p or C-Arc1p alone does not complement an arc1-los1- phenotype, but coexpression of the two domains does. Our data demonstrate that Trbp111 or p43 may replace C-Arc1p to complement an arc1-los1- strain. The two functional domains of Arc1p (N-Arc1p and C-Arc1p) are required to get rid of the synthetic lethal phenotype but do not need to be physically linked. To get some clues to the discrete functions of N-Arc1p and C-Arc1p, we targeted ScMetRS or tIF domains to the nuclear compartment and analyzed their cellular localization by using GFP fusions, and their ability to sustain growth. Our results are consistent with a model according to which Arc1p is a bifunctional protein involved in the subcellular localization of ScMetRS and ScGluRS via its N-terminal domain and of tRNA via its C-terminal domain.
Golinelli-Cohen
Marie-Pierre
MP
Laboratoire d'Enzymologie et Biochimie Structurales, Centre National de la Recherche Scientifique, 1 Avenue de la Terrasse, Gif-sur-Yvette 91190, France.
Mirande
Marc
M
D000951:Antigens, Neoplasm / Q000737:chemistry; D002384:Catalysis; D003593:Cytoplasm / Q000201:enzymology*; D005975:Glutamate-tRNA Ligase / Q000378:metabolism*; D006801:Humans; D008718:Methionine-tRNA Ligase / Q000378:metabolism*; D050296:Microbial Viability; D024101:Mitochondrial Proteins; D008954:Models, Biological; D010444:Peptide Elongation Factor Tu / Q000737:chemistry; D017434:Protein Structure, Tertiary; D012343:RNA, Transfer / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000201:enzymology* / Q000254:growth & development; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism*; D012996:Solutions
C102145:ARC1 protein, S cerevisiae; D000951:Antigens, Neoplasm; D024101:Mitochondrial Proteins; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D012996:Solutions; C091648:TUFM protein, human; D012343:RNA, Transfer; D010444:Peptide Elongation Factor Tu; D008718:Methionine-tRNA Ligase; D005975:Glutamate-tRNA Ligase