title: Mutation of a cleavage site adjacent to the mature domain leads to increase in secreted mature BMP-2 with reduced activity.
abstract: Proteolytic cleavage of precursor bone morphogenetic protein (proBMP) is an important step in generating the active mature BMP. ProBMP-2 contains two proprotein convertase (PC) recognition sites (S1 and S2) and is postulated to be cleaved by PCs at those sites. Cell lines expressing proBMP-2, with a silenced S1 site (mS1) that inhibited PC cleavage, secreted the 20-kDa form BMP-2, while cells expressing wild type (wt) BMP-2 secreted 18- and 20-kDa mature BMP-2 N-terminal isoforms. The mS1 cells secreted 15-fold more mature BMP-2 than the wt, despite their similar mRNA levels. Mutant-secreted BMP-2 demonstrated biological activity in vitro; however, its activity was reduced compared with wt. These data demonstrate that proBMP-2 can be cleaved at an alternative cleavage site without prior S1 site cleavage in cell lines overexpressing BMP-2 and more importantly suggest that the presence of the 2-kDa linker peptide can affect activity and secretion of the mature protein.
authors.affiliation: Oral & Maxillofacial Surgery, University of Toronto, Toronto, ON, Canada.
authors.forename: Aileen J
authors.initials: AJ
authors.lastname: Zhou
authors.forename: Zhining
authors.initials: Z
authors.lastname: Zhu
authors.forename: Cameron M L
authors.initials: CM
authors.lastname: Clokie
authors.forename: Sean A F
authors.initials: SA
authors.lastname: Peel
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000235:genetics / Q000378:metabolism*; D016466:CHO Cells; D006224:Cricetinae; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D010455:Peptides / Q000737:chemistry; D016133:Polymerase Chain Reaction / Q000379:methods; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid
chemical_list: C525718:BMP2 protein, human; C525719:Bmp2 protein, mouse; D055396:Bone Morphogenetic Protein 2; D010455:Peptides; D020033:Protein Isoforms