Involved in bone homeostasis. Acts as a negative regulator of RANKL-induced osteoclast precursor differentiation from bone marrow precursors (By similarity). Expressed in osteoblast cell lines. Well expressed in ovary, heart, pancreas, skeletal muscle, lung, and fetal kidney and lung and only at the basal levels in the other tissues examined including adult kidney. More expressed in S-type neuroblastoma cells than in N-type neuroblastoma cells.