CaM-induced shift of inactivation in hNa<sub>V</sub>1.4 channels.

<p>Representative Na<sup>+</sup> currents and I–V relationships for wild type (<b>A</b>) and hNa<sub>V</sub>1.4<sub>F1705I</sub> channels (<b>B</b>) elicited by the same pulse protocol shown in the inset of <a href="" target="_blank">Figure 1B</a>. CaM and CaM<sub>1234</sub> over expression significantly (p<0.05) shifts the wild type but not the hNa<sub>V</sub>1.4<sub>F1705I</sub> I–V in the depolarizing direction. (<b>C</b>) Representative steady-state inactivation currents elicited from different holding potentials. (<b>D, E</b>) Plots of the steady-state inactivation and activation relationships of wild type hNa<sub>V</sub>1.4 (<b>D</b>) and hNa<sub>V</sub>1.4<sub>F1705I</sub> channels (<b>E</b>). The solid lines are the fits to steady-state inactivation data with CaM and CaM<sub>1234</sub> over expression. There is a significant (p<0.005) depolarizing shift of the inactivation curve by CaM and CaM<sub>1234</sub> compared to the expression of hNa<sub>V</sub>1.4<sub>F1705I</sub> alone. The symbols and colors are the same in all panels of the figure.</p>