Search Organism: All OrganismsArabidopsis thalianaBacillus subtilis 168Bos taurusCaenorhabditis elegansCanis familiarisDanio rerioDrosophila melanogasterEquus caballusEscherichia coli K12Gallus gallusHomo sapiensMacaca mulattaMus musculusNematostella vectensisOryza sativaPan troglodytesRattus norvegicusSaccharomyces cerevisiaeSchizosaccharomyces pombeStrongylocentrotus purpuratusTakifugu rubripesXenopus laevis home help / support contribute downloads mirrors about us BMC Mol. Biol. (2008); 9:22 A novel mutant of the Sup35 protein of Saccharomyces cerevisiae defective in translation termination and in GTPase activity still supports cell viability- Fabret C, Cosnier B, Lekomtsev S, Gillet S, Hatin I, Le Marechal P, Rousset JP IGM, Univ Paris-Sud, UMR 8621, Orsay, F 91405, France- celine-fabret@igmors-u-psud-fr Abstract: BACKGROUND- When a stop codon is located in the ribosomal A-site, the termination complex promotes release of the polypeptide and dissociation of the 80S ribosome- In eukaryotes two proteins eRF1 and eRF3 play a crucial function in the termination process- The essential GTPase Sup35p, the eRF3 release factor of Saccharomyces cerevisiae is highly conserved- In particular, we observed that all eRF3 homologs share a potential phosphorylation site at threonine 341, suggesting a functional role for this residue- The goal of this study was to determine whether this residue is actually phosphorylated in yeast and if it is involved in the termination activity of the protein- RESULTS- We detected no phosphorylation of the Sup35 protein in vivo- However, we show that it is phosphorylated by the cAMP-dependent protein kinase A on T341 in vitro- T341 was mutated to either alanine or to aspartic acid to assess the role of this residue in the activity of the protein- Both mutant proteins showed a large decrease of GTPase activity and a reduced interaction with eRF1-Sup45p- This was correlated with an increase of translational readthrough in cells carrying the mutant alleles- We also show that this residue is involved in functional interaction between the N- and C-domains of the protein- CONCLUSION- Our results point to a new critical residue involved in the translation termination activity of Sup35 and in functional interaction between the N- and C-domains of the protein- They also raise interesting questions about the relation between GTPase activity of Sup35 and its essential function in yeast- [PUBMED: 18267004] Copyright © 2009, Tyers Lab, The Samuel Lunenfeld Research Institute, Mount Sinai Hospital, All Rights Reserved. terms and conditions - privacy policy - Osprey Network Visualization System BioGRID: A General Repository for Interaction Datasets. Chris Stark, Bobby-Joe Breitkreutz, Teresa Reguly, Lorrie Boucher, Ashton Breitkreutz, Mike Tyers. Nucleic Acids Res. Jan 1;34:D535-9.