BMP signaling pathways in cartilage and bone formation.

This review focuses on the molecular aspects of osteogenesis and chondrogenesis as they relate to cellular and developmental levels. We discuss BMP (bone morphogenetic protein)-mediated signaling pathways for the patterning of skeletal elements and mechanisms for the induction of cartilage and bone formation. We emphasize BMP-mediated initiation of chondrogenesis and osteogenesis and consider BMP-dependent signaling cascades in mesenchymal progenitor cells during the development of the axial and appendicular skeleton and during growth plate and joint formation. In particular, we discuss BMP-signaling mediators of the Smad and TAK family and the modulation of these signals by cross-talk and integration with other signaling pathways.