A line graph showing FSign2 as a function of Cai. The x-axis represents Cai values ranging from 0.0 to 1.0. The y-axis represents FSign2 values ranging from 0 to 12. The graph features a single red line that starts at the origin, rises sharply to a peak near 0.2 on the x-axis and 12 on the y-axis, then decreases with a smaller peak around 0.4 on the x-axis and 8 on the y-axis, and finally rises slightly again near 1.0 on the x-axis. All values are approximated.