Critical Role for Saccharomyces cerevisiae Asc1p in Translational Initiation at Elevated Temperatures

The eukaryotic ribosomal protein RACK1/Asc1p is localized to the mRNA exit channel of the 40S subunit but lacks a defined role in mRNA translation. Saccharomyces cerevisiae deficient in ASC1 exhibit temperature‐sensitive growth. Using this null mutant, potential roles for Asc1p in translation and ri...

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Bibliographic Details
Published in:Proteomics (Weinheim) 2018-12, Vol.18 (23), p.e1800208-n/a
Main Authors: Gerbasi, Vincent R., Browne, Christopher M., Samir, Parimal, Shen, Bingxin, Sun, Ming, Hazelbaker, Dane Z., Galassie, Allison C., Frank, Joachim, Link, Andrew J.
Format: Article
Language:English
Subjects:
Adaptor Proteins, Signal Transducing - metabolism
ASC1
Baking yeast
Deletion mutant
GTP-Binding Proteins - metabolism
Heat stress
Heat tolerance
Heat-Shock Response - genetics
Heat-Shock Response - physiology
High temperature
initiation
mRNA
Polyribosomes
Protein Binding
Protein Biosynthesis - genetics
Protein Biosynthesis - physiology
Proteins
Ribosomal proteins
ribosome
Ribosomes
Ribosomes - metabolism
RNA processing
rRNA
Saccharomyces cerevisiae
Saccharomyces cerevisiae - genetics
Saccharomyces cerevisiae - metabolism
Saccharomyces cerevisiae Proteins - metabolism
Temperature
Temperature effects
Translation
Translation initiation
Yeast
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Summary:The eukaryotic ribosomal protein RACK1/Asc1p is localized to the mRNA exit channel of the 40S subunit but lacks a defined role in mRNA translation. Saccharomyces cerevisiae deficient in ASC1 exhibit temperature‐sensitive growth. Using this null mutant, potential roles for Asc1p in translation and ribosome biogenesis are evaluated. At the restrictive temperature the asc1Δ null mutant has reduced polyribosomes. To test the role of Asc1p in ribosome stability, cryo‐EM is used to examine the structure of 80S ribosomes in an asc1Δ yeast deletion mutant at both the permissive and nonpermissive temperatures. CryoEM indicates that loss of Asc1p does not severely disrupt formation of this complex structure. No defect is found in rRNA processing in the asc1Δ null mutant. A proteomic approach is applied to survey the effect of Asc1p loss on the global translation of yeast proteins. At the nonpermissive temperature, the asc1Δ mutant has reduced levels of ribosomal proteins and other factors critical for translation. Collectively, these results are consistent with recent observations suggesting that Asc1p is important for ribosome occupancy of short mRNAs. The results show the Asc1 ribosomal protein is critical in translation during heat stress.
ISSN:1615-9853
1615-9861
DOI:10.1002/pmic.201800208