Osteoprotegerin is basic glycoprotein that in humans is encoded by the TNFRSF11B gene. It is produced by osteoblasts and other mesenchymal cells, lacks a transmembrane domain and acts as a secreted decoy receptor which is a member of the tumor necrosis factor (TNF) receptor superfamily that has no direct signaling capacity. OPG acts by binding to its natural ligand OPGL, which is also known as RANKL (receptor activator of NF-kappa B ligand). This...