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. 2014 Jul 18;592(Pt 18):4025–4038. doi: 10.1113/jphysiol.2014.273177

Figure 3. Caveolin has no effect on Kir2.1 single channel current amplitude and cumulative open probability.

Figure 3

A, representative current traces from −40 mV and −80 mV from HEK293T cells co-transfected with either Kir2.1+GFP (Kir) or Kir2.1+Cav-YFP (Kir/Cav) in a cell-attached configuration. Multiple channels were observed in most membrane patches in both conditions. In any given patch more channels were routinely observed at a more negative membrane voltage (−80 mV) compared to a less negative membrane voltage (−40 mV). The closed level is indicated by the continuous line and the open levels are indicated by dotted lines. B, average unitary conductance of Kir2.1 channels was calculated from the slopes of the linear fits between –40 mV and −80 mV. In the control condition (absence of caveolin) the conductance of Kir was 21 pS and in the presence of caveolin the conductance of Kir was 23 pS. Therefore unitary conductance of Kir2.1 channels was the same relatively unaltered by overexpression of caveolin. C, bar graph summarizing the mean open probabilities are shown. In the case of cells transfected with Kir2.1+GFP (Kir) the mean open probability 0.794 ± 0.0414 and with Kir2.1+Cav-YFP (Kir/Cav) mean open probability was 0.878 ± 0.044. D, representative all-point histograms of channel records at −40 mV and −80 mV are shown for cells transfected with either Kir2.1+GFP (Kir) or Kir2.1+Cav-YFP (Kir/Cav). Cav, caveolin.