The FOV averages of the SA-647/GFP fluorescence ratio per cell for the CaCl 2 concentrations shown in c ( n = 7 FOVs per condition; 0 mM versus 2.5 mM: P = 7.6 × 10 −4 ; 0 mM versus 5 mM: P = 8.8 × 10 −7 ; 0 mM versus 7.5 mM: P = 5.5 × 10 −10 ; 0 mM versus 10 mM: P = 5.4 × 10 −12 ; Tukey’s post hoc multiple-comparison’s test following a one-way ANOVA, F 4,30 = 44.07, P = 3.8 × 10 −12 ). The FOV average SA-647/GFP ratios were linearly correlated with CaCl 2 concentration (two-tailed Pearson’s correlation coefficient R = 0.99, P = 0.001).
