Extended Data Figure 7: Patch-clamp analysis of the wild type hsPANX1 and its mutants.
a, Representative traces of whole-cell current density from patch-clamped tsA201 control cells (N=6) and tsA201 cells overexpressing: wt-hsPANX1 (n=12), ΔNTH (n=5), W74A (n=8), R75E (n=5), N255A (n=5), Δ21–23 (n=6), Δ21–27 (n=7), R29A (n=9), A33W (n=10), A33W/ΔCTT (n=4), ΔCTT (n=4), and A33C (n=5). Voltage steps (0.25 s) of 20 mV were imposed from −100 mV to +80 mV from a holding potential of −10 mV. Cells were first measured in standard bath solution and then re-measured following the superfusion of a bath solution containing 0.1 mM carbenoxolone. b, Mean current measured at 5 ms of experiments in (a) plotted as a function of clamp voltage. c, Current amplitudes of experiments in (a) with and without carbenoxolone. Each paired point represents an individual cell and the bar represents the mean. d, Plot of zero-current reversal potentials using a 2 s voltage ramp for various bath solutions containing either (in mM): 145 NaCl, 145 Na-Iodide, 145 Na-Gluconate, 14.5 NaCl, or 145 NMDG-Cl (see Methods for complete solutions). The number of cells patched (indicated in parenthesis) for the various bath solutions were as follows, 145 mM NaCl: WT (5), R29A (7), W74A (5), R75E (7); 145 mM NaI: WT (5), R29A (7), W74A (5), R75E (7); 145 mM Na-gluconate: WT (5), R29A (7), W74A (5), R75E (7); 14.5 NaCl mM WT (4), R29A (4), W74A (5), R75E (5); 145 mM NMDG-Cl WT (3), R29A (2), W74A (5), R75E (3). e, and f, Plots of the calculated (see methods) permeability of iodide relative to chloride, PI/PCl, the permeability of Gluconate relative to chloride, PGluconate/PCl, and permeability of sodium relative to chloride, PNa/PCl for WT and mutant channels. For statistical comparisons to WT, one-way ANOVA with Bonferroni correction was performed. The p values for the PI/PCl ratios are 0.99, 3.7×10−5, 5.9×10−5 for R29A, W74A, and R75E, respectively. The p values for the PGluconate/PCl ratios are 0.046, 0.99, 6.8×10−9 for R29A, W74A, and R75E, respectively. The p values for the PNa/PCl ratios are 0.99, 0.99, 2.2×10−6 for R29A, W74A, and R75E, respectively. Each point represents an individual cell and the bar represents the mean value. All error bars are SEM.