Figures & data
Figure 1. Channel properties of C-terminally truncated hPanx1. (A) Examples of carbenoxolone-sensitive current obtained from HEK293T cell expressing full-length or C-terminal truncated (ΔC; same as Δ371 in ref. Citation22) hPanx1 using whole-cell voltage ramp. Note that the full-length hPanx1 does not generate appreciable current. (B) Representative whole-cell recording of hPanx1ΔC with different concentration of HEPES- in the bath. Voltage ramps started with symmetrical Cl- (151 mM), followed by replacing Cl- with HEPES- in the bath while maintaining total anion concentration (Cl- + HEPES- = 161 mM). Note the shift in reversal potential (Erev). Similar results were obtained by measuring tail currents at different repolarization steps following a constant depolarization step (data not shown). (C) Plot of reversal potential obtained in bath solutions containing different HEPES concentrations. Red dots indicated averaged Erev from recordings shown in (B). The dashed lines represent fits to an extended constant field (GHK) equationCitation69 using relative permeability ratios (PHEPES:PCl of either 0.3 or 0). The data indicate a substantial HEPES permeability in the C-terminally truncated hPanx1 channel. (D) Example of cell-attached recordings of hPanx1ΔC in HEK293T cells at the indicated patch potentials. The patch contained at least 2 active Panx1 channels, as noted by the transitions from the closed state (C) to 1 (O1) and 2 (O2) channel openings of equal amplitude. Carbenoxolone (CBX) inhibited open probability without changing unitary current amplitude, as reported previously.Citation34 We did not observe multiple subconductance states,Citation23 even in long duration recordings. (E) Unitary conductance (γ) obtained by analyzing single-channel current amplitude at various patch potentials (from data in [D]).
![Figure 1. Channel properties of C-terminally truncated hPanx1. (A) Examples of carbenoxolone-sensitive current obtained from HEK293T cell expressing full-length or C-terminal truncated (ΔC; same as Δ371 in ref. Citation22) hPanx1 using whole-cell voltage ramp. Note that the full-length hPanx1 does not generate appreciable current. (B) Representative whole-cell recording of hPanx1ΔC with different concentration of HEPES- in the bath. Voltage ramps started with symmetrical Cl- (151 mM), followed by replacing Cl- with HEPES- in the bath while maintaining total anion concentration (Cl- + HEPES- = 161 mM). Note the shift in reversal potential (Erev). Similar results were obtained by measuring tail currents at different repolarization steps following a constant depolarization step (data not shown). (C) Plot of reversal potential obtained in bath solutions containing different HEPES concentrations. Red dots indicated averaged Erev from recordings shown in (B). The dashed lines represent fits to an extended constant field (GHK) equationCitation69 using relative permeability ratios (PHEPES:PCl of either 0.3 or 0). The data indicate a substantial HEPES permeability in the C-terminally truncated hPanx1 channel. (D) Example of cell-attached recordings of hPanx1ΔC in HEK293T cells at the indicated patch potentials. The patch contained at least 2 active Panx1 channels, as noted by the transitions from the closed state (C) to 1 (O1) and 2 (O2) channel openings of equal amplitude. Carbenoxolone (CBX) inhibited open probability without changing unitary current amplitude, as reported previously.Citation34 We did not observe multiple subconductance states,Citation23 even in long duration recordings. (E) Unitary conductance (γ) obtained by analyzing single-channel current amplitude at various patch potentials (from data in [D]).](/cms/asset/740bd63d-5ac1-4ad2-a67e-97643b288d02/kchl_a_10927545_f0001.gif)