Receptor activator of nuclear factor-κB ligand–osteoprotegerin signaling pathway (RANK–RANKL–OPG pathway)

The RANK–RANKL–OPG signaling pathway is a fundamental regulatory system for bone metabolism, immune function, and cancer progression. RANKL (encoded by TNFSF11) is a member of the TNF ligand superfamily expressed by osteoblasts and other cells, acting as a critical factor for osteoclast differentiation and activation upon binding its receptor RANK (on osteoclasts, dendritic cells, epithelial cells, etc.). OPG serves as a soluble decoy receptor, blocking RANKL and thus inhibiting osteoclastogenesis and bone resorption. Aberrant activation of the pathway drives pathological bone loss (osteoporosis) and tumor bone metastasis, while therapeutic RANKL inhibition (e.g., denosumab) is used in bone diseases and cancer. The pathway’s roles extend to immune regulation, mammary gland development, and tissue remodeling in cardiovascular disease.

Other names

RANKL/RANK/OPG pathwayRANK–RANKL–OPG axisRANKL pathwayRANK pathwayOPG pathwayRANKL (also known as TNFSF11, OPGL, ODF, TRANCE)

RANKL inhibitors (e.g., denosumab) bind RANKL, preventing its interaction with RANK, thus inhibiting osteoclast formation and bone resorption. OPG acts as a decoy receptor, naturally inhibiting RANKL signaling.