Fig. 5.

Functional rescue of the mutation L281S by HSP90β (A–G). Whole-cell current traces recorded, in response to depolarization from −80 to +50 mV in 10 mV steps in HEK293T cells transfected with the indicated combination of the KCNQ4 channel and HSP90β. (A) 0.5 μg WT KCNQ4+2.5 μg vector; (B) 0.5 μg L281S + 2.5 μg vector; (C) 0.25 μg L281S + 0.25 μg WT KCNQ4+2.5 μg vector; (D)0.5 μg WT KCNQ4 + 2.5 μg HSP90β, (E) 0.5 μg L281S + 2.5 μg HSP90β, (F) 0.25 μg L281S + 0.25 μg WT KCNQ4+2.5 μg HSP90β, (G) non-transfected cells as negative control. (H) Average current densities (mean ± SEM of 5–7 cells, *P ≤ 0.05, **P ≤ 0.01). The average current density of the mutant L281S was significantly lower than that of the WT channel. No significant differences in current densities were found in cells expressing L281S alone or co-expressing L281S/WT, L281S/HSP90β, or L281S/WT/HSP90β.