RYR2 and diabetes mellitus: In diabetes, reduced expression of transporters and channels responsible for Ca2+i homeostasis (sarcoendoplasmic reticulum Ca2+-ATPase 2a (SERCA2a), the ryanodine receptor type 2 (RyR2), the sarcolemma Na+-Ca2+ exchanger, and the L-type Ca2+ channel) may be due to the lack of insulin or insulin effect as a growth factor [24,27,28,29].