Receptor activator of nuclear factor kappa-B (RANK) (RANK)

Receptor activator of nuclear factor kappa-B (RANK) is a type I transmembrane protein and a member of the tumor necrosis factor receptor (TNFR) superfamily (UniProtKB Q9Y6Q6). It acts as the essential receptor for RANK ligand (RANKL), forming a signaling complex that is the master regulator of osteoclast differentiation, activation, and survival (GeneCards, 2024). In bone homeostasis, the RANK/RANKL/OPG signaling axis controls the balance of bone resorption and formation, while its dysregulation is central to the pathogenesis of osteoporosis, Paget's disease, and bone destruction in metastatic cancer (PubMed, 2007). Beyond its skeletal role, RANK is involved in mammary gland development, lymph node organogenesis, and the mediation of thermoregulation and fever responses (NCBI, 2026). It also plays a key role in the immune system by facilitating communication between dendritic cells and T cells (PubMed, 2001). The primary clinical agent affecting this target is denosumab, a monoclonal antibody that binds to RANKL to prevent its interaction with the RANK receptor, thereby inhibiting excessive bone resorption (Frontiers, 2020). Current therapeutic research is expanding to evaluate RANK as a prognostic marker and a potential target for immunomodulation in various cancers (Frontiers, 2021).

Interruption of the RANKL-RANK signaling axis to inhibit the differentiation, activation, and survival of osteoclasts, primarily through the suppression of downstream NF-kB, JNK, and MAPK pathways [PubMed: 11485016, 2001; Frontiers in Endocrinology, 2023].