FIGURE 3.

Assessing the calcium fluxes of individual FDB fibers following Orai1 manipulation. (A) Line-scan image of the kinetic analysis of Ca²⁺-release fluxes for transients elicited by a train of depolarizing pulses to +30 mV at 1 Hz frequency, lasting 200 ms each in Cmpt FDB fibers reconstructed with venus-Orai1. The white trace depicts the spatially averaged F(t)/F₀. (B) The SR Ca²⁺ content was estimated from the amount released minus the removal flux. A single-exponential function was fitted to the points (for further details please see Eq. A10 in Appendix A from Sztretye et al., 2017). Note that there is a sharp decrease of the SR calcium content following the first depolarizing pulse. (C) Pooled data of the calculated fluxes (K1) through Orai1 channels as predicted by our model (see Appendix A from Sztretye et al., 2017). Reconstructing the mutant fibers with venus-Orai1 restored the Ca²⁺ fluxes to the levels previously seen in WT fibers (consult Sztretye et al., 2017, Figure 4F). The numbers in parenthesis denote the number of cells studied.