Figure 3.

Cardiac Perm1 is enriched in the ventricle and becomes decreased in failing human heart. A, the protein levels of Perm1 in the atrium, ventricle, and GAST muscles were determined by western blot analysis and quantified (right panel). Arrows indicate the two major protein isoforms encoded for by Perm1. (Expression of Perm1 protein was first normalized to GAPDH in each sample and then relative amounts were determined relative to atrial expression, which was set = 1.) Data are the mean ± SD, expressed relative to the atrium (n = 3). ∗p < 0.05 versus ventricle. B, adult mice heart tissue was subjected to subcellular fractionation, followed by western blotting. Antibodies against Perm1 (top panel), cytoplasmic GAPDH, mitochondrial Cox, sarcoplasmic reticulum SERCA2a, and nuclear lamins (shown as four western blots beneath Perm1) were used to assess the purity of the cytoplasmic, mitochondrial, SR (sarcoplasmic reticulum), and nuclear fractions. Representative images from three independent experiments are shown. C, total RNA was extracted from the ventricles of adult mice subjected to Sham or TAC surgery. mRNA levels for Perm1 were determined by RT-qPCR, normalized by 36B4 levels, and expressed relative to normalized expression in Sham-treated mice that were set = 1. (n = 6–8). D, whole tissue protein extracted from the ventricles of Sham or TAC mice was subjected to western blot with antibodies indicated (Perm1 and GAPDH). (n = 4). E, whole tissue protein extracted from the left ventricle of DCM (dilated cardiomyopathy) patients and normal subjects (Control) was evaluated with western blot using the antibodies indicated. (n = 6) Data are the mean ± SD, expressed relative to sham or control. ∗p < 0.05; ∗∗p < 0.01.