Poly(A)-binding protein acts in translation termination via eukaryotic release factor 3 interaction and does not influence [PSI(+)] propagation.
Recent studies of translational control suggest that translation termination may not be simply the end of synthesizing a protein but rather be involved in modulating both the translation efficiency and stability of a given transcript. Using recombinant eukaryotic release factor 3 (eRF3) and cellular extracts, we have shown for Saccharomyces cerevisiae that yeast eRF3 and Pab1p can interact. This interaction, mediated by the N+M domain of eRF3 and amino acids 473 to 577 of Pab1p, was demonstrated to be direct by the two-hybrid approach. We confirmed that a genetic interaction exists between eRF3 and Pab1p and showed that Pab1p overexpression enhances the efficiency of termination in SUP35 (eRF3) mutant and [PSI(+)] cells. This effect requires the interaction of Pab1p with eRF3. These data further strengthen the possibility that Pab1p has a role in coupling translation termination events with initiation of translation. Several lines of evidence indicate that Pab1p does not influence [PSI(+)] propagation. First, "[PSI(+)]-no-more" mutations do not affect eRF3-Pab1p two-hybrid interaction. Second, overexpression of PAB1 does not cure the [PSI(+)] phenotype or solubilize detectable amounts of eRF3. Third, prion-curing properties of overexpressed HSP104p, which is required for formation and maintenance of [PSI(+)], were not modified by excess Pab1p.
Cosson
Bertrand
B
Universite de Rennes 1, CNRS UMR 6061, 35043 Rennes Cedex, France.
Couturier
Anne
A
Chabelskaya
Svetlana
S
Kiktev
Denis
D
Inge-Vechtomov
Sergey
S
Philippe
Michel
M
Zhouravleva
Galina
G
D002352:Carrier Proteins / Q000378:metabolism; D003598:Cytoskeletal Proteins; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D006801:Humans; D010454:Peptide Termination Factors / Q000235:genetics / Q000378:metabolism*; D039102:Poly(A)-Binding Proteins; D011328:Prions; D011485:Protein Binding; D014176:Protein Biosynthesis; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D020798:Two-Hybrid System Techniques
D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; D005656:Fungal Proteins; D010454:Peptide Termination Factors; D039102:Poly(A)-Binding Proteins; D011328:Prions; D016601:RNA-Binding Proteins; D018160:Receptors, Cytoplasmic and Nuclear; C082265:SLA1 protein, S cerevisiae; C068068:SUP35 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C087971:peptide-chain-release factor 3