Fig. 7
From: Voltage-gated sodium channels assemble and gate as dimers
Cardiac sodium channels display coupled gating at the single-channel level which can be uncoupled by 14-3-3 inhibition. a Single-channel representative traces for WT, WT+ difopein and S460A at −40 mV. The overall amplitudes for single and double openings are represented as mean ± SEM in the gray bars. The dotted lines correspond to single-level openings (O1) and double-level openings (O2) respectively. The number of channel under a patch was estimated by the amplitude and detected by the Clampfit analysis software. b Number of openings in function of time. 600 hundred sweeps were recorded by depolarizing the membrane at −40 mV and the number of openings of level 1 (uncoupled) or openings of level 2 (coupled) were plotted in function of time. c Representative examples of uncoupled openings versus coupled openings. The uncoupled openings are non-simultaneous as opposed to the coupled opening which present a simultaneous opening of the dimer. Importantly, the loss of double-level openings results in a drastic increase of single-level openings in presence of difopein or S460A mutant and strongly supports the uncoupling of the dimers
