GDF-3 is a member of the BMP family of TGF-beta superfamily proteins, and is highly homologous to GDF-9. The GDF (Growth/Differentiation Factor) group of proteins is characterized by a polybasic proteolytic processing site which is cleaved to produce a mature protein. With the exception of GDF-3 and -9, GDF dimers are disulfide-linked proteins. GDF-3 is a secreted protein and is expressed in undifferentiated embryonic stem (ES) cells, ossifying bone, brain, bone marrow, spleen, thymus, and adipose tissue. This protein displays inhibitory activity towards other TGF-beta superfamily members including BMPs, and participates in regulatory functions in embryogenesis. GDF­3 has been shown to be induced by a high fat diet, and is associated with adipogenesis and obesity.