Inhibitor of bone morphogenetic proteins (BMP) signaling. Controls somitogenesis by sequestering the BMP-4 activity which in turn differentiates distinct subtypes of the mesoderm along the mediolateral axis. Homodimer. At stage 8 (4-6 somites) expressed in two prominent regions, the notochord and the one posterior to Hensen node. At stage 14 (20 somites) expressed in the lateral border of the segmental plate. As the somite stage proceeds, detected in the lateral and medial portion of a young and old somite respectively and is also localized in the notochord and the roof plate of the neural tube. By sonic ectopic hedgehog. Belongs to the noggin family.