Mediates beneficial effects of muscular exercise. Induces browning of white adipose tissue by stimulating UCP1 expression, at least in part, via the nuclear receptor PPARA. Imported in peroxisomes through the PEX5 receptor pathway. Detected in the blood of individuals subjected to endurance exercise. In adult, it is highly expressed in skeletal muscle, heart and brain. During embryonic development, it is detected almost exclusively in the skeletal muscle, and at lower level in brain. In skeletal muscle, it is induced after myoblast differentiation, when myotube formation is promoted. Up-regulated by muscular exercise. This effect can be mediated, at least partly, by PPARGC1A. The extracellular domain is cleaved and released from the cell membrane. N-Glycosylated.