Measuring the dependence of the yeast heat shock response on intracellular pH during stress

S. cerevisiae cells acidify when they experience stressful temperatures. To determine whether this heat-shock associated acidification is important for the cellular response, we manipulated intracellular pH, heat shocked cells, and sequenced the transcriptome. Overall design: Diploid yeast cells (BY4743 expressing 1 copy of SSA4 tagged genomically with mCherry and expressing pHluorin from the leu locus) were heat shocked (42C for 20 minutes) with and without ionophore treatment at 2 pH values; samples were collected just after treatment. Ionophore treatment at 6.8 mimicks normal cellular acidification; treatment at 7.4 prevents pH change during heat shock.