SMAD1

SMAD1 is a polypeptide that is a homolog of a Drosophila gene. It belongs to the SMAD family of proteins, which modulate the TGFβ superfamily of ligands. Like many other TGFβ family modulators SMAD1 is involved in cell signalling and modulates signals of bone morphogenetic proteins (BMP's). The binding of ligands causes the oligomerization and phosphorylation of the SMAD1 protein. SMAD1 is a receptor regulated SMAD (R-SMAD) and is activated by bone morphogenetic protein type 1 receptor kinase.

Nomenclature
The SMAD proteins are homologs of both the Drosophila protein and the C. elegans protein SMA. The name is a combination of the two.