title: Furin is the major processing enzyme of the cardiac-specific growth factor bone morphogenetic protein 10.
abstract: Bone morphogenetic protein 10 (BMP10) is a member of the TGF-β superfamily and plays a critical role in heart development. In the postnatal heart, BMP10 is restricted to the right atrium. The inactive pro-BMP10 (∼60 kDa) is processed into active BMP10 (∼14 kDa) by an unknown protease. Proteolytic cleavage occurs at the RIRR(316)↓ site (human), suggesting the involvement of proprotein convertase(s) (PCs). In vitro digestion of a 12-mer peptide encompassing the predicted cleavage site with furin, PACE4, PC5/6, and PC7, showed that furin cleaves the best, whereas PC7 is inactive on this peptide. Ex vivo studies in COS-1 cells, a cell line lacking PC5/6, revealed efficient processing of pro-BMP10 by endogenous PCs other than PC5/6. The lack of processing of overexpressed pro-BMP10 in the furin- and PACE4-deficient cell line, CHO-FD11, and in furin-deficient LoVo cells, was restored by stable (CHO-FD11/Fur cells) or transient (LoVo cells) expression of furin. Use of cell-permeable and cell surface inhibitors suggested that endogenous PCs process pro-BMP10 mostly intracellularly, but also at the cell surface. Ex vivo experiments in mouse primary hepatocytes (wild type, PC5/6 knock-out, and furin knock-out) corroborated the above findings that pro-BMP10 is a substrate for endogenous furin. Western blot analyses of heart right atria extracts from wild type and PACE4 knock-out adult mice showed no significant difference in the processing of pro-BMP10, implying no in vivo role of PACE4. Overall, our in vitro, ex vivo, and in vivo data suggest that furin is the major convertase responsible for the generation of BMP10.
authors.affiliation: Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, Université de Montréal, Montreal, Quebec H2W 1R7, Canada.
authors.forename: Delia
authors.initials: D
authors.lastname: Susan-Resiga
authors.forename: Rachid
authors.initials: R
authors.lastname: Essalmani
authors.forename: Josée
authors.initials: J
authors.lastname: Hamelin
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Asselin
authors.forename: Suzanne
authors.initials: S
authors.lastname: Benjannet
authors.forename: Ann
authors.initials: A
authors.lastname: Chamberland
authors.forename: Robert
authors.initials: R
authors.lastname: Day
authors.forename: Dorota
authors.initials: D
authors.lastname: Szumska
authors.forename: Daniel
authors.initials: D
authors.lastname: Constam
authors.forename: Shoumo
authors.initials: S
authors.lastname: Bhattacharya
authors.forename: Annik
authors.initials: A
authors.lastname: Prat
authors.forename: Nabil G
authors.initials: NG
authors.lastname: Seidah
mesh_terms: D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000235:genetics / Q000378:metabolism*; D019556:COS Cells; D002522:Chlorocebus aethiops; D045683:Furin / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D006352:Heart Ventricles / Q000201:enzymology*; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D009206:Myocardium / Q000201:enzymology*; D009928:Organ Specificity; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology
chemical_list: C541386:BMP10 protein, human; C119152:Bmp10 protein, mouse; D019485:Bone Morphogenetic Proteins; D015842:Serine Proteinase Inhibitors; D045683:Furin