TNFRSF11B (Tumor Necrosis Factor Receptor Superfamily Member 11B): TNFRSF11B is a protein, also known as osteoprotegerin, that plays a crucial role in bone metabolism. It functions as a decoy receptor for RANKL, helping to inhibit osteoclast formation and prevent bone resorption. TNFRSF11B is vital for maintaining bone density and strength, and alterations in its function are linked to osteoporosis and other bone disorders.