Figure 9. Cytosolic Ca²⁺ dependency of phosphorylation state mutant InsP₃R-1 constructs.

Pooled data from cells expressing AA or EE InsP₃R-1 at the [Ca²⁺] indicated and a pipette solution containing 0.5 μm ADO and 0.5 mm ATP. The P_o was normalized to the maximal P_o for each construct (n > 5 for each [Ca²⁺]). The black curves are the Hill equation fits of the AA and EE InsP₃R-1 data. The red curve represents the Hill equation fit of the WT InsP₃R-1 data reproduced from Fig. 3. The Ca²⁺ dependency for the activation or inhibition of InsP₃R-1 activity was not significantly different when comparing either construct or when compared to WT InsP₃R-1 (see Fig. 3).