Osteoprotegerin/Fc Chimera (OPG) Human Active Protein

The protein encoded by this gene is a member of the TNF-receptor superfamily. This protein is an osteoblast-secreted decoy receptor that functions as a negative regulator of bone resorption. This protein specifically binds to its ligand, osteoprotegerin ligand, both of which are key extracellular regulators of osteoclast development. Studies of the mouse counterpart also suggest that this protein and its ligand play a role in lymph-node organogenesis and vascular calcification. Alternatively spliced transcript variants of this gene have been reported, but their full length nature has not been determined. [provided by RefSeq, Jul 2008]

TNFRSF11B: Acts as decoy receptor for RANKL and thereby neutralizes its function in osteoclastogenesis. Inhibits the activation of osteoclasts and promotes osteoclast apoptosis in vitro. Bone homeostasis seems to depend on the local RANKL/OPG ratio. May also play a role in preventing arterial calcification. May act as decoy receptor for TRAIL and protect against apoptosis. TRAIL binding blocks the inhibition of osteoclastogenesis. Defects in TNFRSF11B are the cause of juvenile Paget disease (JPD); also known as hyperostosis corticalis deformans juvenilis or hereditary hyperphosphatasia or chronic congenital idiopathic hyperphosphatasia. JPD is a rare autosomal recessive osteopathy that presents in infancy or early childhood. The disorder is characterized by rapidly remodeling woven bone, osteopenia, debilitating fractures, and deformities due to a markedly accelerated rate of bone remodeling throughout the skeleton. Approximately 40 cases of JPD have been reported worldwide. Unless it is treated with drugs that block osteoclast- mediated skeletal resorption, the disease can be fatal.

Protein type: Secreted, signal peptide; Inhibitor; Secreted

Chromosomal Location of Human Ortholog: 8q24

Cellular Component: extracellular space; proteinaceous extracellular matrix; extracellular region

Molecular Function: cytokine activity; receptor activity

Biological Process: response to drug; response to magnesium ion; extracellular matrix organization and biogenesis; apoptosis; response to estrogen stimulus; negative regulation of odontogenesis of dentine-containing teeth; response to arsenic; signal transduction; negative regulation of bone resorption; skeletal development; response to nutrient

Disease: Paget Disease, Juvenile