Panel A shows a line trace of current from reconstituted rabbit RyR1. The vertical axis represents the number of channels open, and the horizontal axis represents time in milliseconds. The trace displays fluctuations in the number of simultaneously open channels over time. Panel B presents another line trace representing a single realization of the Markov chain for a 4-channel couplon. The vertical axis represents the number of channels open, and the horizontal axis represents time in milliseconds. The trace shows transitions between different channel occupancy states over time. Panel C features a histogram comparing the all-points distributions of experimental data, simulation results, and an independent 4-channel binomial model. The horizontal axis represents current in channels open, and the vertical axis represents probability. The histogram shows differences between the experimental and simulated distributions relative to the binomial distribution, indicating robust coupling and coordinated behavior among neighboring channels.
Simulations with a 4-channel couplon compared with data in bilayers. (A) Current from reconstituted rabbit RyR1 showing four levels by Porta et al. (2012), digitized from the original graph reprinted in Fig. 2 A. (B) Single realization of the Markov chain representing a 4-channel couplon. A low-pass filter (0.5 kHz) was applied, for better visual comparison with the experimental data. (C) All-points histograms of the experimental data (red), the simulation (grey), and the independent 4-channel set (“Binomial,” Eq. 17). Note the difference of both experimental and simulated distributions with the binomial, indicating robust inter-channel coupling. Also, that coupling in the sense used by Porta et al. (2012) of simultaneous or quasi-simultaneous gating, is intermittent in both experiment and simulation. And finally, that state m = 3 (three channels open) occurs more frequently than m = 2 in both experiment and simulation.