RANK (receptor activator of NF-kB) is a member of the TNFR family, identified as a dendritic cell membrane protein. Murine sRANK Ligand is a soluble 19.4 kDa protein, comprising the TNF-like extracellular domain of RANKL (174 amino acids). The full length of RANK Ligand is 39.6 kDa containing 36 amino acids.