Skip to main content
. 2016 Sep 1;6:32444. doi: 10.1038/srep32444

Figure 7. Co-chaperones and chaperones increase the functional expression of CLC-1.

Figure 7

Electrophysiological analyses of Flag-CLC-1 WT and A531V mutant channels in HEK293T cells. (A) The effect of FKBP8 co-expression. (Left panels) Representative cell-attached and whole-cell patch clamp recordings of WT and A531V, respectively. The holding potential was 0 mV. The voltage protocol comprised a 200-ms test pulse (Vm) ranging from +100 mV to −140 mV in −20 mV steps, followed by a second voltage step (tail potential) to −100 mV for 200 ms. (Upper right panels) Instantaneous cell-attached current amplitudes (WT) or whole-cell current densities (A531V) at the test pulse potential of −140 mV were used for normalization with respect to the corresponding vector control. The mean relative current levels for WT and A531V are about 1.9 and 2.5, respectively. (Lower right panels) Steady-state voltage-dependence of the open probability (Po–V curve) of CLC-1 channels. Compared to CLC-1 WT, the A531V mutant displays an apparently left-shifted Po–V curve, which primarily arises from the different cytoplasmic ATP concentrations between cell-attached (WT) and whole-cell (A531V) configurations (refer to Suppl. Fig. S3 for experimental evidence). See Supplementary Methods for more details on the analysis of Po–V curves. (B) The effect of Aha1 co-expression. The mean relative current levels for WT and A531V are about 1.4 and 2.5, respectively. (C) The effect of HOP co-expression. The mean relative current levels for WT and A531V are about 1.5 and 1.9, respectively. (D) The effect of Hsc70 co-expression. The mean relative current levels for WT and A531V are about 2.2 and 2.3, respectively. (E) The effect of Hsp90β co-expression. The mean relative current levels for WT and A531V are about 2.7 and 2.7, respectively. (F) The effect of treatment with 1 μM 17-AAG. The mean relative current levels for WT and A531V are about 3.5 and 2.0, respectively. Two types of drug-free incubation (control and 0.1% DMSO) were used to verify the effect of 17-AAG. Asterisks denote a significant difference from the control condition (*, t-test: p < 0.05).