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Critical Role for Saccharomyces cerevisiae Asc1p in Translational Initiation at Elevated Temperatures
Author(s) -
Gerbasi Vincent R.,
Browne Christopher M.,
Samir Parimal,
Shen Bingxin,
Sun Ming,
Hazelbaker Dane Z.,
Galassie Allison C.,
Frank Joachim,
Link Andrew J.
Publication year - 2018
Publication title -
proteomics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.26
H-Index - 167
eISSN - 1615-9861
pISSN - 1615-9853
DOI - 10.1002/pmic.201800208
Subject(s) - ribosomal protein , ribosome , translation (biology) , ribosome biogenesis , biology , eukaryotic small ribosomal subunit , microbiology and biotechnology , ribosomal rna , 30s , saccharomyces cerevisiae , eukaryotic ribosome , initiation factor , mutant , temperature sensitive mutant , protein biosynthesis , messenger rna , genetics , yeast , rna , gene
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.