Succinate activates the CaMKII δ hypertrophic signaling pathway. A. Immunoblot for CaMKIIδ of whole cell lysates from primary cultures of neonatal cardiomyocytes. B. Bar graph shows that succinate significantly increases CAMKIIδ levels. These results represent the mean ± S.E. of three separate experiments. (**p < 0.01). C. Representative images of cardiomyocytes immunostained with antibodies against HDAC5 (green), α-actinin (red) and DAPI (blue). Succinate decreased HDAC5 nuclear export. Scale bar represents 10 μm. KN93 is a selective CaMKIIδ inhibitor. Nuclear export of HDAC5 induced by succinate is dependent on CaMKIIδ. D. Quantification of the nuclear fluorescence for HDAC5 (*p < 0.05, **p < 0.01). E. Summary of cellular area (**p < 0.01, ***p < 0.001), 45 cells).