Mothers against decapentaplegic homolog 5 also known as SMAD5 is a
protein that in humans is encoded by the SMAD5gene.[5]
SMAD5, as its name describes, is a homolog of the
Drosophila gene: "
Mothers against decapentaplegic", based on a tradition of such unusual naming within the gene research community.[6] It belongs to the
SMAD family of proteins, which belong to the
TGFβ superfamily of modulators. Like many other TGFβ family members SMAD5 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 SMAD5 protein. SMAD5 is a
receptor regulated SMAD (
R-SMAD) and is activated by bone morphogenetic protein type 1 receptor kinase. It may play a role in the pathway where TGFβ is an inhibitor of
hematopoietic progenitor cells.