Fig. 1

Expression of osteopontin, CD44, CaMKII and Ca²⁺-handling proteins in β-AR-activated CD44^−/− mice at different time points during treatment with β-AR agonist. A Representative examples and mean ± SE analysis western blot for osteopontin, CD44, ox-CaMKII, (p-)CaMKII, (p-)RyR2, SERCA, NCX and (p-)PLN. The relative expression of each protein was quantified to GAPDH by densitometry and normalized to the control. N = 4 for each group. B Representative examples and mean ± SE analysis for co-immunoprecipitation of CD44 and control IgG with Epac1 and Epac2. C Representative examples and mean ± SE analysis for co-immunoprecipitation of CD44 and PKAc and PKAIIα. In B and C, the pictures are representation of blots from 3 independent experiments for each. the mean ± SE analysis was for precipitated protein-bound CD44 and Epac1 to precipitated protein ratio and cell input, both of which were quantified to GADPH and normalized to the control (WT without ISO) level, which was set at 1.0. N = 3 for each group. For A–C *P < 0.05 versus control (WT and CD44^−/− mice without ISO) by one-way ANOVA with Bonferroni’s post hoc test. ^#P < 0.05 between groups by unpaired Student’s t-test. D Representative co-focal images of CD44 (upper, green color), Epac1 (middle, red color) and co-localization of both (lower, yellow color) and mean ± SE analysis of co-localization in WT and CD44^−/− mice heart after 48-h ISO. The relative fluorescence of co-localization was normalized to WT mice as 1.0. N = 4 per group. For D, *P < 0.05 versus control by one-way ANOVA with Bonferroni’s post hoc test. WT = wild-type control, CD44^−/− = CD44 knock-out mice, ISO = isoproterenol at 30 mg/kg per day subcutaneously