Recombinant Drosophila Decapentaplegic (Dpp) Protein

Decapentaplegic (Dpp) is one of at least five TGF-beta superfamily ligands identified in the Drosophila genome. Dpp, a functional orthologue of mammalian BMP-2 and BMP-4, is a morphogen and plays an essential role in Drosophila development. Dpp regulates embryonic dorsal-ventral polarity and is required for gut morphogenesis and outgrowth and patterning of imaginal disks. Similar to other TGF-beta family ligands, Dpp is synthesized as a large proprotein which is proteolytically processed at the dibasic cleavage site to release the carboxy-terminal domain. Biologically active Dpp is a disulfide-linked homodimer of the carboxy-terminal 132 amino acid residues that contains the characteristic conserved cysteine residues involved in the formation of the cysteine knot and the interchain disulfide bond. Cellular responses to Dpp have been shown to be mediated by the ligand-induced formation of heteromeric complexes of the Drosophila type I, Thick Veins (Tkv), and type II, Punt, serine/threonine kinases. The activated receptor complex induces the phosphorylation of the prototypical Smad, Mad, and subsequent translocation of the Mad-Medea complex to the nucleus where they regulate the transcription of target genes. Secreted extracellular Dpp antagonists, including the short-gastrulation (Sog) and twisted gastrulation (TSG), which bind Dpp and regulate its availability, have been identified.