Figure 1.

Schematic diagram of intracellular mechanisms for Ca²⁺ regulation by sarcoplasmic reticulum and mitochondria in obese and type 2 diabetic skeletal muscle. Obesity and type 2 diabetes mellitus may cause impairments in Ca²⁺ release capacity via a decrease in content or oxidation of RyR. On the other hand, there is no effect on SERCA activity. Note that the mitochondria also have an important sequestration role during the recovery process through a uniporter in OMM or IMM. IMM, The Inner Mitochondrial Membrane; MCUs, Mitochondrial Calcium Uniporter(s); Mfns, Mito Fusion 1 and/or 2; OMM, The Outer Mitochondrial Membrane; ROS, Reactive Oxygen Species; RyR, Ryanodine Receptor; SERCA, Sarcoplasmic reticulum Ca²⁺-ATPase; VDAC, Voltage Gated-Dependent Anion Channel.