Noggin binds to and antagonizes bone morphogenetic protein (BMP) ligands of the transforming growth factor beta (TGF-β) family. Noggin supports maintenance of undifferentiated human embryonic stem cells in vitro, and can be used to prevent spontaneous differentiation in the short term (Chaturvedi et al.). Noggin is essential for development of structures derived from ectoderm embryonic somite, skeletal patterning, and neurogenesis in vivo. It also influences chondrogenesis, osteogenesis, and joint formation (Krause et al.), and promotes dopaminergic differentiation of embryonic stem cells and subsequent survival of dopamine neurons (Chiba et al.).