Figure 5.

RyR2^Δβ8–β9 displays drastically altered intracellular Ca²± release dynamics. Single-cell Ca2+ imaging using confocal laser scanning microscopy to monitor spontaneous Ca²⁺ release transient events. (A) Traces from Fluo-3 loaded single HEK293 cells expressing RyR2WT or RyR2^Δβ8–β9 showing spontaneous Ca²⁺ transients and Ca²⁺ release induced by caffeine (1 mmol/L, 10 mmol/L) or thapsigargin (1 μmol/L). (B) Ca²⁺ transient characteristics, including amplitude, duration, and frequency of events, were analysed for 84 cells expressing RyR2^WT and 81 cells expressing RyR2^Δβ8–β9 from four separate experiments, whereas the caffeine response for at least 20 cells. The ER Ca²⁺ store content was measured by integration of the (1 μmol/L) thapsigargin-induced Ca²⁺ release (following 1 mmol/L caffeine application) at the end of each experiment. Data are normalized for RyR2^WT and expressed as mean value ± SEM; statistical analysis was carried out using Mann–Whitney test.