TGF-β/BMP signaling in cartilage and bone cells

Cartilage and bone formation, a continual process in both vertebrate development and adult bone remodeling, is regulated by many growth factorq 64s. Transforming Growth Factors (TGF-βs) and Bone Morphogenetic Proteins (BMPs), members of the TGF-β superfamily, are the most potent regulators of chondrocyte and osteoblast differentiation among the local factors governing the process of biomineralization. To gain a better understanding of the molecular mechanisms underlying the role of TGF-β/BMP in normal cartilage and bone formation, as well as in cartilage and bone diseases, it is necessary to clarify the TGF-β/BMP signaling transduction pathways in chondrocytes and osteoblasts. Thus far, primary signaling cascades downstream of the TGF-β/BMP have been elucidated. The major objective of this review is to summarize the TGF-β/BMP signaling pathways in chondrocytes and osteoblasts. In particular, this discourse will focus on recent advances of the role of different ligands, receptors, Smads and Smad-interacting transcription factors in cartilage and bone formation during embryonic development and postnatal osteogenesis.