title: Paired basic/Furin-like proprotein convertase cleavage of Pro-BMP-1 in the trans-Golgi network.
abstract: Bone morphogenetic protein (BMP)-1 is a zinc-dependent metalloproteinase that cleaves a variety of extracellular matrix substrates, including type I procollagen. Little is known about the site of action of BMP-1, although the extracellular matrix seems likely to be it. BMP-1 is synthesized with an N-terminal prodomain. The removal of the prodomain presumably activates the proteinase. In this study we show that the prodomain is cleaved in the trans-Golgi network (TGN) and by furin-like/paired basic proprotein convertases. Inhibitors of furin resulted in the secretion of pro-BMP-1, which could not cleave procollagen. Recombinant furin cleaved the prodomain from pro-BMP-1. Site-directed mutagenesis of the prodomain cleavage site (RSRR) to RSAA resulted in efficient secretion of pro-BMP-1. Therefore, prodomain cleavage was not required for secretion. Using peptide N-glycosidase and neuraminidase digestion to determine the post-translational status of pro-BMP-1 during its conversion to BMP-1, we showed that BMP-1 first appears in the TGN during sialylation of the molecule. Furthermore, immunofluorescence studies using an antibody to the nascent N terminus of BMP-1 showed localization to the TGN and plasma membrane. The observation that BMP-1 occurs inside the cell raises the possibility that BMP-1 might begin to cleave its substrates prior to secretion to the extracellular matrix.
authors.affiliation: Wellcome Trust Centre for Cell-Matrix Research, School of Biological Sciences, University of Manchester, Stopford Building 2.205, Oxford Road, Manchester M13 9PT, United Kingdom.
authors.forename: Mat
authors.initials: M
authors.lastname: Leighton
authors.forename: Karl E
authors.initials: KE
authors.lastname: Kadler
mesh_terms: D000581:Amidohydrolases / Q000378:metabolism; D015153:Blotting, Western; D055395:Bone Morphogenetic Protein 1; D019485:Bone Morphogenetic Proteins / Q000737:chemistry / Q000378:metabolism*; D020126:Brefeldin A / Q000494:pharmacology; D002462:Cell Membrane / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D000939:Epitopes; D005109:Extracellular Matrix / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism; D045683:Furin; D015723:Gene Library; D006801:Humans; D008666:Metalloendopeptidases / Q000737:chemistry / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D008985:Monensin / Q000494:pharmacology; D016297:Mutagenesis, Site-Directed; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D013381:Subtilisins / Q000737:chemistry; D014162:Transfection; D014407:Tumor Cells, Cultured; D021601:trans-Golgi Network / Q000378:metabolism*
chemical_list: D019485:Bone Morphogenetic Proteins; D018076:DNA, Complementary; D000939:Epitopes; D011994:Recombinant Proteins; D020126:Brefeldin A; D008985:Monensin; D013381:Subtilisins; D045683:Furin; D008666:Metalloendopeptidases; C525705:BMP1 protein, human; D055395:Bone Morphogenetic Protein 1; D000581:Amidohydrolases; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase