Succinate activates the ERK1/2 hypertrophic signaling pathway. A. Immunoblot of whole cell lysates showing increased phosphorylation of ERK1/2 and absence of phosphorylated ERK1/2 when GPR91 is silenced with siRNA. B. Bar graph shows that succinate significantly increases phosphorylation of ERK1/2 levels and fails to increase ERK1/2 phosphorylation when GPR91 is efficiently silenced. These results represent the mean ± S.E. of three separate experiments (**p < 0.01). C. Cells were treated with succinate and ERK1/2 inhibitor PD 098059. Immunofluorescence staining with DAPI (blue), anti-α-actinin (red) and ANP (green). D-E. Summary of cellular area and fluorescence intensity indicating that inhibition of ERK1/2 signaling pathway reverses the hypertrophic effect of succinate. (**p < 0.01, n = 50 cells).