Figure 4. Predictions of mitochondrial Ca²⁺ uptake as a function of extra-matrix [Ca²⁺] for a range of ΔΨ and as a function ΔΨ for a range of extra-matrix [Ca²⁺] based on our present alternate model of mitochondrial Ca²⁺ uniporter.

Simulations are shown only for Model 1 under Case 1 with the biophysical parameters β _e and β _x as functions of ΔΨ. Plot A shows the model predicted Ca²⁺ uptake in response to varying extra-matrix Ca²⁺ corresponding to the experimental protocol of Scarpa and Graziotti [12] for a range of ΔΨ. Plot B shows the model predicted Ca²⁺ uptake in response to varying extra-matrix Ca²⁺ corresponding to the experimental protocol of Vinogradov and Scarpa [13] for a range of ΔΨ. In these simulations, ΔΨ was varied from 100 mV to 210 mV and matrix [Ca²⁺] was fixed at 0.25 µM. Plot C shows the model predicted Ca²⁺ uptake as a function of ΔΨ corresponding to the experimental protocol of Wingrove et al. [16] with extra-matrix [Ca²⁺] ranging from 10 µM to 150 µM and matrix [Ca²⁺] fixed at 0.25 µM. The model uses the parameter values estimated based on the present uniporter model (Table 2).