Yeast heat shock response at 37C, 42C and 46C

Life is resilient because living systems are able to respond to elevated temperatures with an ancient gene expression program called the heat shock response (HSR). Our global analysis revealed a modular HSR dependent on the severity of the stress in yeast. Interestingly, at all temperatures analyzed, the transcription of hundreds of genes is upregulated among them the molecular chaperones, which protect proteins from aggregation. However, for approximately 90% of the regulated genes, the function under stress remained enigmatic. Surprisingly, the majority of these upregulated genes is translated but only for a small fraction this results in raised proteins levels. In this context, increased translation is required to counter-balance elevated protein turnover at elevated temperatures. This anaplerotic reaction together with the molecular chaperone system allows yeast to buffer proteotoxic stress. When the capacity of this system is exhausted at extreme temperatures, translation is stopped via phase transition and growth stops. Overall 18 samples (including 2 control samples at 25C) are measured in triplicates or duplicates