title: Cleavages within the prodomain direct intracellular trafficking and degradation of mature bone morphogenetic protein-4.
abstract: Pro bone morphogenetic protein-4 (BMP-4) is initially cleaved at a consensus furin motif adjacent to the mature ligand domain (the S1 site), and this allows for subsequent cleavage at an upstream motif (the S2 site). Previous studies have shown that S2 cleavage regulates the activity and signaling range of mature BMP-4, but the mechanism by which this occurs is unknown. Here, we show that the pro- and mature domains of BMP-4 remain noncovalently associated after S1 cleavage, generating a complex that is targeted for rapid degradation. Degradation requires lysosomal and proteosomal function and is enhanced by interaction with heparin sulfate proteoglycans. Subsequent cleavage at the S2 site liberates mature BMP-4 from the prodomain, thereby stabilizing the protein. We also show that cleavage at the S2, but not the S1 site, is enhanced at reduced pH, consistent with the possibility that the two cleavages occur in distinct subcellular compartments. Based on these results, we propose a model for how cleavage at the upstream site regulates the activity and signaling range of mature BMP-4 after it has been released from the prodomain.
authors.affiliation: Department of Biochemistry and Molecular Biology, Oregon Health and Science University, School of Medicine, Portland, OR 97239-3098, USA.
authors.forename: Catherine
authors.initials: C
authors.lastname: Degnin
authors.forename: François
authors.initials: F
authors.lastname: Jean
authors.forename: Gary
authors.initials: G
authors.lastname: Thomas
authors.forename: Jan L
authors.initials: JL
authors.lastname: Christian
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D001692:Biological Transport; D015153:Blotting, Western; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000737:chemistry* / Q000378:metabolism*; D018076:DNA, Complementary / Q000378:metabolism; D045683:Furin / Q000737:chemistry; D019812:Heparan Sulfate Proteoglycans / Q000737:chemistry; D006639:Histidine / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D047468:Immunoprecipitation; D007700:Kinetics; D008024:Ligands; D008247:Lysosomes / Q000378:metabolism; D008954:Models, Biological; D009865:Oocytes / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D020543:Proteome; D015398:Signal Transduction; D014981:Xenopus; D029867:Xenopus Proteins
chemical_list: D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D018076:DNA, Complementary; D019812:Heparan Sulfate Proteoglycans; D008024:Ligands; D020543:Proteome; D029867:Xenopus Proteins; C525812:bmp4 protein, Xenopus; D006639:Histidine; D045683:Furin