Regulation of SERCA pumps expression in diabetes.

Cytosolic calcium concentration ([Ca(2+)]c) is fundamental for regulation of many cellular processes such metabolism, proliferation, muscle contraction, cell signaling and insulin secretion. In resting conditions, the sarco/endoplasmic reticulum (ER/SR) Ca(2+) ATPase's (SERCA) transport Ca(2+) from the cytosol to the ER or SR lumen, maintaining the resting [Ca(2+)]c about 25-100nM. A reduced activity and expression of SERCA2 protein have been described in heart failure and diabetic cardiomyopathy, resulting in an altered Ca(2+) handling and cardiac contractility. In the diabetic pancreas, there has been reported reduction in SERCA2b and SERCA3 expression in β-cells, resulting in diminished insulin secretion. Evidence obtained from different diabetes models has suggested a role for advanced glycation end products formation, oxidative stress and increased O-GlcNAcylation in the lowered SERCA2 expression observed in diabetic cardiomyopathy. However, the role of SERCA2 down-regulation in the pathophysiology of diabetes mellitus and diabetic cardiomyopathy is not yet well described. In this review, we make a comprehensive analysis of the current knowledge of the role of the SERCA pumps in the pathophysiology of insulin-dependent diabetes mellitus type 1 (TIDM) and type 2 (T2DM) in the heart and β-cells in the pancreas.