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. Author manuscript; available in PMC: 2011 Dec 21.
Published in final edited form as: Circulation. 2010 Nov 15;122(25):2669–2679. doi: 10.1161/CIRCULATIONAHA.110.982298

Figure 3. CaMKII phosphorylation induces RyR2 mediated SR calcium leak and reduced SR calcium load in intact myocytes.

Figure 3

(A) Representative Ca2+ transients (left) and superimposed SR load traces (right) expressed as F/F0. (B) Average twitch Ca2+ transient amplitude (DF/F0) in WT, S2814D, and S2814A cardiomyocytes. (C) Averaged peak fluorescence ratio (DF/F0) obtained by 10 mM caffeine application in WT, S2814D, and S2814A cardiomyocytes. (D) Fractional Ca2+ release expressed as ratio for twitch Ca2+ transient/caffeine transient in WT, S2814D, and S2814A cardiomyocytes. (E and F) CaMKII phosphorylation activates RyR2. RyR2 open probablity (Po) is increased in S2814D mice (see box plot in F) as calculated from RyR2 single channel recordings (n=14 channels for each group) (E). N is indicated in bar graphs. 2-way repeated measures ANOVA was used to compare Ca2+ imaging data. The Mann-Whitney U-test was used to compare Po. *P<0.05, **P<0.01, ***P<0.001 versus WT.