title: Inhibition of convertase-related processing of proendothelin-1.
abstract: The biologically inactive precursor proendothelin-1 (proET-1) is initially processed intracellularly to the intermediate big endothelin peptide (big ET-1) before its conversion to the endothelin-1 (ET-1) peptide by the endothelin-converting enzyme (ECE). We recently demonstrated that purified furin, a calcium-dependent serine endoprotease belonging to the family of mammalian convertases, cleaved proET-1 in vitro and hence produced the physiologically relevant big ET-1 peptide. Therefore, furin becomes a candidate proET-1-cleaving enzyme responsible for the initial biosynthetic processing steps of this precursor. In this study we examined the inhibitory properties of two convertase inhibitors, i.e., the decanoyl-Arg-Val-Lys-Arg-chloromethylketone (dec-RVKR-cmk) and the alpha 1-antitrypsin Portland (AT-PDX) on proET-1 processing. When purified furin or PACE4, another mammalian convertase, was incubated in the presence of dec-RVKR-cmk, proET-1 processing was completely abolished. In the presence of purified AT-PDX, furin-related cleavage of proET-1 was abolished but not PACE4 processing. In addition, incubation of endothelial cells with dec-RVKR-cmk inhibited production of ET-1 but did not significantly alter the levels of the prostanoid PGI2. These results indicate that convertase-related processing of proET-1 can be inhibited in vitro and in vivo, and that convertase-specific processing may be prevented with AT-PDX.
authors.affiliation: Department of Pharmacology, Medical School, Université de Sherbrooke, Québec, Canada.
authors.forename: J B
authors.initials: JB
authors.lastname: Denault
authors.forename: P
authors.initials: P
authors.lastname: D'Orléans-Juste
authors.forename: T
authors.initials: T
authors.lastname: Masaki
authors.forename: R
authors.initials: R
authors.lastname: Leduc
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D019332:Endothelin-1; D016232:Endothelins / Q000378:metabolism*; D045683:Furin; D008969:Molecular Sequence Data; D011498:Protein Precursors / Q000378:metabolism*; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology*; D013381:Subtilisins / Q000037:antagonists & inhibitors*; D000515:alpha 1-Antitrypsin / Q000494:pharmacology
chemical_list: D019332:Endothelin-1; D016232:Endothelins; D011498:Protein Precursors; D015842:Serine Proteinase Inhibitors; D000515:alpha 1-Antitrypsin; C093240:proendothelin 1; D013381:Subtilisins; D045683:Furin