Noggin is a disulfide-linked homodimer that acts by binding members of the TGF-β family, and consequently blocks their ability to signal through their receptors. Noggin plays a crucial role in regulating developmental processes by inhibiting the signaling pathway of bone morphogenetic protein 4 (BMP-4), as well as other BMPs. During embryogenesis Noggin is produced by the dorsal mesoderm and is important for the correct bone morphology and neural tissue formation. Mutations in the Noggin-coding gene (NOG) are associated with several bone diseases. The sequence of Noggin protein shows high homology across several species.