Protein degradation and dynamic tRNA thiolation fine-tune translation at elevated temperatures.
Bottom Line: In agreement with previous transcriptomics studies, amongst the most marked changes, we found up-regulation of cytoprotective factors; a shift from oxidative phosphorylation to fermentation; and down-regulation of translation.Using random forests we show that this results in differential translation of transcripts with a biased content for the corresponding codons.We propose that the role of this pathway in promoting catabolic and inhibiting anabolic processes, affords cells with additional time and resources needed to attain proper protein folding under periods of stress.
Affiliation: MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.Show MeSH
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Mentions: Laxman et al. (45) have recently shown that tRNA hypothiolation in cells starved for sulfur containing amino acids (S-AA) can be rescued by deleting NPR2. To test if hypothiolation in cells grown at elevated temperatures is controlled in a similar fashion, we first analysed the down-regulation of thiolation in S-AA starved cells by RNA-MS and northern blot analysis (Figure 4A and B). This indicated that S-AA starvation and growth at elevated temperatures had similar effects on tRNA modification. However, although S-AA starvation induced tRNA hypothiolation was effectively suppressed in an npr2Δ strain (Figure 4C compare change in thiolation level between lanes 1, 2 (npr2Δ background) to that between lanes 4, 5 (wt background)), the same was not the case for temperature induced hypothiolation (Figure 4C compare change in thiolation level between lanes 1, 3 (npr2Δ background) to that between lanes 4, 6 (wt background)). Furthermore, the latter was not rescued by methionine supplementation, nor by growing the cells in a complex rich media (Figure 4D).
Affiliation: MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.