Fig. 1.

Mechanisms of osteoblast and osteoclast function induced by Wnt signalling. a When the pathway is activated, osteoblasts differentiate and through mature osteoblast upregulation of OPG inhibit RANKL-induced osteoclastogenesis preventing bone resorption. b When the pathway is arrested, osteoblast proliferation and differentiation also cease, causing the precursors of mature osteoblasts to activate RANKL. Osteoclastogenesis and bone resorption follow. OPG osteoprotegerin, RANKL receptor activator of NF-κB ligand (modified from [8])