Yeast Uri1p promotes translation initiation and may provide a link to cotranslational quality control.
Translation initiation in eukaryotes is accomplished by a large set of translation initiation factors, some of which are regulated by signals monitoring intracellular and environmental conditions. Here, we show that Uri1p is required for efficient translation initiation in budding yeast. Indeed, uri1Delta cells are slow growing, sensitive to translation inhibitors and they exhibit an increased 80S peak in polysome profiles. Moreover, GCN4 translation is derepressed in uri1Delta cells, strongly supporting an initiation defect. Genetic and biochemical experiments indicate that Uri1p interacts with the translation initiation factor eIF1A and promotes ternary complex (TC) recruitment to the 40S subunit. Interestingly, we found that Uri1p is also part of a chaperone-network, including the prefoldin Pfd6p and several other proteins involved in cotranslational quality control such as the ribosome-associated Hsp70 chaperone Ssb1p, the Hsp40 Sis1p and the translation elongation factor eEF1A. Together with genetic data, these interactions indicate that Uri1p may coordinate translation initiation and cotranslational quality control.
Deplazes
Anna
A
Department of Biology, Institute of Biochemistry, ETH Zurich, Zurich, Switzerland. anna.deplazes@bc.biol.ethz.ch or
Möckli
Natalie
N
Luke
Brian
B
Auerbach
Daniel
D
Peter
Matthias
M
D050976:Basic-Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins / Q000096:biosynthesis; D015977:Eukaryotic Initiation Factor-1 / Q000378:metabolism; D017353:Gene Deletion; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000378:metabolism; D010448:Peptide Initiation Factors / Q000235:genetics / Q000502:physiology*; D011485:Protein Binding; D014176:Protein Biosynthesis; D025941:Protein Interaction Mapping; D012440:Saccharomyces / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014157:Transcription Factors / Q000096:biosynthesis
D050976:Basic-Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins; D015977:Eukaryotic Initiation Factor-1; C501391:GCN4 protein, S cerevisiae; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D010448:Peptide Initiation Factors; C070320:SIS1 protein, S cerevisiae; C090869:SSA3 protein, S cerevisiae; C095192:SSB1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C541141:Uri1 protein, S cerevisiae; C026022:eukaryotic peptide initiation factor-1A