Irisin and Myonectin Regulation in the Insulin Resistant Muscle: Implications to Adipose Tissue: Muscle Crosstalk

Figure 1

Stimulation of irisin secretion by cold and exercise. Irisin secretion results from PGC-1a activation, which leads to FNDC5 expression. FNDC5 present in the membrane is in turn cleaved and irisin is secreted to the blood, acting on the adipose tissue in order to stimulate the formation of brite adipocytes and UCP-1 expression. Irisin also seems to induce AMPK phosphorylation in the skeletal muscle itself. AMPK: AMP-activated protein kinase; FNDC5: fibronectin type-III domain containing protein 5; PGC-1α: peroxisome proliferator-activated receptor gamma coactivator 1-α; UCP-1: uncoupling protein-1.