C1q And Tumor Necrosis Factor Related Protein 2 (C1QTNF2)

Adiponectin is an important adipokine, which participates in the regulation of energy metabolism. Unlike adiponectin, which is expressed exclusively in adipocytes, C1QTNFs are expressed in a wide variety of tissues and appear to have diverse functions. C1QTNF1, which is expressed by vascular smooth muscle cells, inhibits collagen-induced platelet aggregationand activates Akt and MAPK. C1QTNF3 is expressed by chondrocytes, and recombinant C1QTNF3 stimulates cartilage development by activating extracellular signal-regulated kinase (ERK) and Akt signaling pathway. Recently, it was reported that C1QTNF2 induces the phosphorylation of AMPK in C2C12 myocytes, resulting in increased glycogen accumulation and fatty acid oxidation. However, C1QTNF2 is not present in plasma, which indicates that other C1QTNFs act on muscle and liver cells to regulate metabolism.