Structure-based mechanism of RyR channel operation by calcium and magnesium ions
Fig 10
Description of RyR open probability data by the COI model of RyR operation.
The data points represent the mean and SEM of the single-channel open probability values read from the referenced publications (see below). The curves represent the theoretical predictions of the COI model (Eq. 3) with the corresponding parameters for individual data groups in Table 8. A – Calcium dependence of the single-channel PO at cytosolic [Mg2+] of 0, 600, and 940 µM (indicated next to the data) in the presence of 3 mM cytosolic ATP and 1 mM luminal Ca2+. Black points – canine RyR2 channels [36]. Green points - rat RyR2 channels [61]. Lines - theoretical predictions of the COI model with parameters for the “RyR2 + ATP” group in Table 8. B – Magnesium dependence of the single-channel PO at cytosolic [Ca2+] of 0.1 and 0.41 µM (indicated next to the data) in the presence of 3 mM cytosolic ATP and 1 mM luminal Ca2+. Green points - rat RyR2 channels [61,62]. Lines - theoretical predictions of the COI model with parameters for the “RyR2 + ATP” group in Table 8. C – Calcium dependence of the single-channel open probability obtained in the absence of cytosolic ATP and Mg2+ and with 10 µM luminal Ca2+ [26,63]. Black points - canine RyR2 channels [26]. Blue points - human RyR1 channels [63]. Red points – rabbit RyR1 channels [26]. Lines - theoretical predictions of the COI model with parameters for the “RyR1 − ATP” or “RyR2 − ATP” groups in Table 8.