Fig. 2

Functional comparison of hNav1.4 with the variants. A Representative current traces for wild-type hNav1.4 (WT), hNav1.4 with L810Q (L810Q), and hNav1.4 with F1519S (F1519S), expressed in HEK293T cells elicited by the activation protocol shown in Fig. 2B, right. B Voltage dependence of steady-state fast inactivation (circles) and activation (squares). Symbols are as follows: WT (filled) and L810Q (opened). C Voltage-dependent kinetics for fast inactivation ranging from −25 mV to +30 mV are shown. These data were obtained from single exponential decay of ionic current decay elicited by an activation protocol (shown in Fig. 2B, right). Error bars indicate SEM. D Cell membrane-targeting assay for WT, F1519S, and mTq2 alone. Note that mTq2 alone is the negative control. The Y-axis shows normalized values of the membrane-targeting efficacy of each clone (F1519S and mTq2 alone) with respect to WT (WT = 1.0, a gray line). F1519S exhibits similar or slightly lower membrane-targeting efficacy, but not zero, compared to WT, indicating that the F1519S channel significantly expresses in the plasma membrane, although it cannot conduct ionic currents as shown in Fig. 2A. Horizontal bars indicate mean ± SD