Figure 2. For hyperosmotic stress, accuracy can be quantified as the statistical dependency between the dynamics of Hog1 and the dynamics of volume recovery.

(A) Characterization of the wild-type (WT) and mutant strains in response to a 1 M sorbitol step. Colours here and in all following figures: blue (WT); green (fast mutant—ssk1$\mathrm{\Delta }$); red (slow mutant—ste11$\mathrm{\Delta }$). Mean responses are shown and error bars are SEM. See also Video 1. (B) Normalized response from wild-type cells to illustrate the degree of matching between the time of adaptation of Hog1 (the time for nuclear Hog1 to undergo a 85% decrease from its maximum) and the time of volume recovery (the time for the volume to undergo a 85% increase from its minimum). (C) Accuracy is the correlation between the adaptation times and is lowest for the fast mutant in late stages of the volume recovery (data from six experiments with at least 500 cells per strain; Figure 2—figure supplement 1). Error bars are 95% confidence intervals for the mean calculated by bootstrapping. (D) Adaptation of Hog1 in single cells becomes less sensitive to the magnitude of the stress in the fast mutant. The mutual information between the distributions of adaptation times of Hog1 and the magnitude of the steps from four experiments shows that the fast mutant becomes the least informative late in adaptation explaining the drop in correlation in C. Error bars are 95% credible intervals for the mean calculated by bootstrapping. Differences between strains are therefore at a 5% significance level when the error bars do not overlap.

DOI: http://dx.doi.org/10.7554/eLife.21415.004

Figure 2—figure supplement 1. The Hog1 and volume response for wild-type and mutants in steps.

(A) Step data used in Figure 2C with the sorbitol concentrations given above each panel. Average and SEM error bars are shown. Numbers of cells are listed in order of wild-type, ste11∆, ssk1∆ for each experiment (n = 78, 112, 94 for 0.2 M; n = 116, 140, 87 for 0.4 M; n = 105, 123, 113 for 0.6 M ; n = 82, 81, 87 for 0.8 M; n = 192, 148, 125 for 1.0 M; n = 133, 89, 94 for 1.2 M). (B) Average volume traces for the experiments shown in A. Error bars are SEM.

DOI: http://dx.doi.org/10.7554/eLife.21415.005

Figure 2—figure supplement 2. Distributions of the adaptation time of Hog1 for different step inputs.

Single-cell distributions of the adaptation time of Hog1 (time to adapt to 85% of the maximum value) for step inputs of 0.6, 0.8, 1 and 1.2 M sorbitol. Adaptation times were found from the experiments of Figure 2—figure supplement 1 and the distributions used to calculate the mutual information in Figure 2D.

DOI: http://dx.doi.org/10.7554/eLife.21415.006