Fig. 5.

Simulated cytosolic Ca²⁺ level (i.e., x(t)) for yvc1 cch1 mutant increases upon extracellular Mg²⁺ depletion or extracellular Ca²⁺ challenge. Panel A, the simulated x(t) response curve (the black curve) for parameter [Mg_ex ] (the red curve) suddenly decreasing from 1 mM to 0 mM at t = 0 and being reset to 1 mM after 90 s (please note that in this simulation, parameter [Ca_ex ] = 150 mM). Panel B, the simulated x(t) response curve (the black curve) for parameter [Ca_ex ] (the red curve) suddenly increasing from 150 mM to 200 mM at t = 0 and being reset to 150 mM after 90 s (please note that in this simulation, parameter [Mg_ex ] = 0 mM). The basal level of [Ca_ex ] in these two simulations is set to be 150 mM instead of 2 mM as in Wiesenberger’s paper [49] because our model is only valid for hypertonic shock (extracellular Ca²⁺ >132 mM). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of the article.)