Recombinant Mouse BMP-9 Protein

Bone morphogenetic protein 9 (BMP-9), also known as growth and differentiation factor 2 (GDF-2), is a member of the BMP family of TGF-beta superfamily proteins that signal through heterodimeric complexes composed of type I and type II BMP receptors. BMP-9 regulates the development and function of a variety of embryonal and adult tissues (1, 2). Mouse BMP-9 consists of a 22 amino acid (aa) signal sequence, a 296 aa propeptide, and a 110 aa mature protein. Unlike other BMP family propeptides, the BMP-9 propeptide does not interfere with the biological activity of BMP-9, and remains associated with the mature peptide after proteolytic cleavage (3). Mouse and human BMP-9 share 96% aa sequence identity. Within the mature protein, mouse BMP-9 shares 64% aa sequence identity with mouse BMP-10 and approximately 50% aa sequence identity with other BMPs. BMP-9 is expressed by non-parenchymal cells in the liver where it promotes lipid metabolism and inhibits glucose production (4 - 6). It exerts a prolonged hypoglycemic effect which may be due to an enhancement of insulin release (6). BMP-9 interacts with the high affinity ALK-1 receptor on liver endothelial cells (3 - 5). It induces a cholinergic neuronal phenotype as well as the differentiation of mesenchymal stem cells into the chondrogenic lineage (7 - 11). At low concentrations, BMP-9 is a proliferative factor for hematopoietic progenitor cells, but at higher concentrations it enhances TGF-beta 1 production, and inhibits hematopoietic progenitor colony formation (12). BMP-9 also inhibits angiogenesis and the invasiveness of prostate carcinoma cells (13, 14).