Table 3.
CaM regulation of wild type and mutant RyRs at 0.1–0.4 µM Ca2+
| Open Probability at 0.1–0.4 µM Ca2+ |
Normalized Open Probability at 0.1–0.4 µM Ca2+ (% no CaM) |
||
|---|---|---|---|
|
|
|||
| no CaM | 50 nM CaM | 1 µM CaM | |
| WT-RyR1 | 0.02 ± 0.01 (6) | 175 ± 22 ^ (6) | 255 ± 32 ** (6) |
| WT-RyR2 | 0.03 ± 0.02 (6) | 57 ± 12 ** (6) | 53 ± 7 ** (5) |
| s-cEF-c | 0.03 ± 0.01 (7) | 58 ± 17 * (7) | 51 ± 10 * (7) |
| s-sEF-c | 0.01 ± 0.01 (7) | 192 ± 41 ^ (7) | 353 ± 78 * (7) |
| s-cEF-s | 0.01 ± 0.01 (8) | 85 ± 12 (8) | 58 ± 8 * (8) |
| s-sEF1-cEF2-s | 0.04 ± 0.02 (4) | 166 ± 25 ^ (4) | 191 ± 21 * (4) |
| s-cEF1-cEF2-s | 0.07 ± 0.02 (5) | 66 ± 7 * (5) | 56 ± 9 ** (5) |
| s-cEF1-sEF2-s | 0.04 ± 0.01 (4) | 107 ± 11 (4) | 98 ± 10 (4) |
| s-sEF1-sEF2-s | 0.02 ± 0.01 (9) | 127 ± 20 (9) | 167 ± 23 * (9) |
| RyR1-EF1mut | 0.01 ± 0.01 (5) | 114 ± 22 (5) | 94 ± 7 (5) |
| RyR1-EF2mut | 0.06 ± 0.01 (4) | 35 ± 13 ** (4) | 21 ± 9 ** (4) |
| RyR2-EF2mut | 0.03 ± 0.01 (6) | 43 ± 12 ** (6) | 38 ± 9 ** (6) |
| RyR2-EF2del | 0.43 ± 0.19 (5) | 84 ± 9 (5) | 61 ± 15 ^ (5) |
| c-cCaMBD-sEF-c | 0.12 ± 0.07 (4) | 66 ± 10 ** (4) | 65 ± 3 ** (4) |
| c-sCaMBD-sEF-c | 0.08 ± 0.03 (4) | 71 ± 8 * (4) | 52 ± 9 ** (4) |
Data are shown as mean ± SEM of the number of experiments indicated in parentheses. All experiments were performed with membrane fractions pretreated with CaMBP. CaM activation and inhibition effects were normalized to the control (no CaM).
^
p<0.05 compared with controls (no CaM addition) by Student’s t-test.
*
p<0.05 and
**
p<0.005 compared with controls by ANOVA followed by Tukey’s test