Receptor Activator of NF-kappa B Ligand (RANK Ligand) is a cell-bound marker (CD254) related to the TNF family of Proteins. RANK Ligand plays a critical role in bone metabolism, particularly osteoclast differentiation. In addition, RANK Ligand is expressed by some T cells is thought to promote dendritic cell matu ion. Recombinant soluble RANK Ligand is a non-glycosylated Protein, containing 174 amino acids, with a molecular weight of 19.9 kDa.