A ribosomal protein is required for translational regulation of GCN4 mRNA. Evidence for involvement of the ribosome in eIF2 recycling.
In amino acid-starved yeast cells, inhibition of the guanine nucleotide exchange factor eIF2B by phosphorylated translation initiation factor 2 results in increased translation of GCN4 mRNA. We isolated a suppressor of a mutant eIF2B. The suppressor prevents efficient GCN4 mRNA translation due to inactivation of the small ribosomal subunit protein Rps31 and results in low amounts of mutant 40 S ribosomal subunits. Deletion of one of two genes encoding ribosomal protein Rps17 also reduces the amounts of 40 S subunits but does not suppress eIF2B mutations or prevent efficient GCN4 translation. Our findings show that Rps31-deficient ribosomes are altered in a way that decreases the eIF2B requirement and that the small ribosomal subunit mediates the effects of low eIF2B activity on cell viability and translational regulation in response to eIF2 phosphorylation.
Mueller
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PP
Institute of Biochemistry and Molecular Biology, University of Berne, CH-3012 Berne, Switzerland. PMU@GBF.DE
Grueter
P
P
Hinnebusch
A G
AG
Trachsel
H
H
D000483:Alleles; D001483:Base Sequence; D017931:DNA Primers; D004268:DNA-Binding Proteins; D020717:Eukaryotic Initiation Factor-2B; D005656:Fungal Proteins / Q000235:genetics*; D020662:Guanine Nucleotide Exchange Factors; D009154:Mutation; D014176:Protein Biosynthesis; D011494:Protein Kinases / Q000235:genetics*; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics*; D012269:Ribosomal Proteins / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins
D017931:DNA Primers; D004268:DNA-Binding Proteins; D020717:Eukaryotic Initiation Factor-2B; D005656:Fungal Proteins; D020662:Guanine Nucleotide Exchange Factors; D011506:Proteins; D012333:RNA, Messenger; D012269:Ribosomal Proteins; D029701:Saccharomyces cerevisiae Proteins; D011494:Protein Kinases