Noggin belongs to a group of diffusible proteins which bind to ligands of the TGF beta family and regulate their activity by inhibiting their access to signaling receptors. The interplay between TGF beta ligands and their natural antagonists has major biological significance during development processes, in which cellular response can vary considerably depending upon the local concentration of the signaling molecule. Noggin was originally identified as a BMP-4 antagonist whose action is critical for proper formation of the head and other dorsal structures. Alternative Names: NOG protein, SYM1 protein, SYNS1 protein , Synostoses (multiple) syndrome 1 protein, SYNS 1 protein, Symphalangism 1 (proximal) protein, SYM 1 protein