RYR1 Sequence Variants in Myopathies: Expression and Functional Studies in Two Families

Figure 4

4-CmC-induced Ca²⁺ release in lymphoblastoid cells from patients 460, 461 ((a) and (b)), and 425 (c) and (d)) expressing the RYR1 c.7035C>A (p.S2345R ), the RYR1 wt/RYR1 c.7035C>A (p.S2345R), and the RYR1 c.9293G>T (p.S3098I)/RYR1 c.14771_14772insTAGACAGGGTGTTGCTCTGTTGCCCTTCTT (p.F4924_V4925insRQGVALLPFF) variant alleles, respectively, and two control cell lines. Cells were stimulated with 4-CmC (200 μM to 1000 μM) or 1 μM TG. Ca²⁺ release was measured at each concentration by calculating the integral of the Fluo-3/Fura Red ratio signal over time ((a) and (c)) and expressed as a percentage of the TG-triggered Ca²⁺ release ((b) and (d)). Experiments were carried out at least three times. Data are reported as mean ± standard error of the mean (SEM). Statistical analysis of responses of patient cell lines with respect to the average of the two control cell lines was performed by the two-tailed Student’s t-test or by one-way analysis of variance followed by Dunnett’s test (p< 0.05).