Fig. 2: Proteins that phase separate in vitro form foci above a quantifiable in vivo c_sat.

a Representative images of mCherry fusion protein foci in E. coli at 4 h post-induction. Phase contrast (PC) (gray), mCherry channel (green), and merged images are shown. Images are representative of three biological replicates. Scale bar: 2 µm. b Percent of cells with a focus over induction time. Solid lines and shading represent the average and standard deviation, respectively, over three biological replicates. N > 100 cells for each protein at each time point per replicate. c Fluorescence concentrations of proteins at times post-induction in cells from (b). Cells were classified for the presence of a focus as in (b). Solid lines and shading represent the average and standard deviation, respectively, over three biological replicates. N > 100 cells for each protein at each time point per replicate. Each data point is shown if it totals at least 10% of the population at its corresponding time point. Light blue shading is added to highlight potential saturation concentration. d Quantification of an apparent cellular c_sat. Cells are classified by the presence or absence of a focus. Data points correspond to individual cells. N > 100 cells for each protein per replicate. Two-sided Welch’s t-test was done on the mean of the replicates. n.s. indicates no statistically significant difference between the samples. Source data are provided as a Source Data file.