Expression of calcium-handling proteins. A. Membranes containing human right atrial cardiac tissue samples from non-diabetic (non-DM) and diabetic (DM) patients were probed for RyR2, SERCA2a, PLB, and GAPDH. RyR2 was detected above 250 kDa, SERCA2a between 100 kDa and 130 kDa, PLB below 10 kDa and for all samples GAPDH above 35 kDa as loading control. Western blot analysis showed similar protein expression for B. RyR2, whereas C. SERCA2a expression was increased and D. the expression of PLB was more than five times lower in the cardiac tissue of diabetic patients. E. Consequently the SERCA2a:PLB ratio showed a four times increase in the diabetic group compared to non-diabetic group. Data are means ± SEM, obtained from four replica experiments using non-DM (n = 16) and DM (n = 8) patient samples, except non-DM for RyR2 from n = 12; * = p < 0.05 vs. non-DM, unpaired t-test.