Osteoprotegerin

Osteoprotegerin (OPG) belongs to TNF receptor superfamily. OPG is expressed in many tissues besides osteoblasts, including heart, kidney, liver, spleen, and bone marrow. Osteoprotegerin plays a critical role in bone remodeling, and has osteoprotective effect. Osteoprotegerin also protects large blood vessels from medial calcification. Osteoprotegerin can bind to RANKL and inhibit the binding between TNFSF11 and RANKL, thereby neutralizing the RANKL function in osteoclastogenesis[1]. OPG is also involved in multiple processes of cancers, such as tumor survival, epithelial to mesenchymal transition (EMT), neo-angiogenesis, invasion, and metastasis. Human osteoprotegerin shares <85% aa sequence identity with mouse and rat. Mouse OX40 shares 94.5% aa sequence identity with rat.