title: Ectodomain shedding and autocleavage of the cardiac membrane protease corin.
abstract: Corin is a cardiac membrane protease that activates natriuretic peptides. It is unknown how corin function is regulated. Recently, soluble corin was detected in human plasma, suggesting that corin may be shed from cardiomyocytes. Here we examined soluble corin production and activity and determined the proteolytic enzymes responsible for corin cleavage. We expressed human corin in HEK 293 cells and detected three soluble fragments of ∼180, ∼160, and ∼100 kDa, respectively, in the cultured medium by Western blot analysis. All three fragments were derived from activated corin molecules. Similar results were obtained in HL-1 cardiomyocytes. Using protease inhibitors, ionomycin and phorbol myristate acetate stimulation, small interfering RNA knockdown, and site-directed mutagenesis, we found that ADAM10 was primarily responsible for shedding corin in its juxtamembrane region to release the ∼180-kDa fragment, corresponding to the near-entire extracellular region. In contrast, the ∼160- and ∼100-kDa fragments were from corin autocleavage at Arg-164 in frizzled 1 domain and Arg-427 in LDL receptor 5 domain, respectively. In functional studies, the ∼180-kDa fragment activated atrial natriuretic peptide, whereas the ∼160- and ∼100-kDa fragments did not. Our data indicate that ADAM-mediated shedding and corin autocleavage are important mechanisms regulating corin function and preventing excessive, potentially hazardous, proteolytic activities in the heart.
authors.affiliation: Department of Molecular Cardiology, Nephrology, and Hypertension, Cleveland Clinic, Cleveland, Ohio 44195, USA.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Jiang
authors.forename: Shannon
authors.initials: S
authors.lastname: Wu
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Shenghan
authors.initials: S
authors.lastname: Chen
authors.forename: Jianhao
authors.initials: J
authors.lastname: Peng
authors.forename: Xiumei
authors.initials: X
authors.lastname: Zhang
authors.forename: Qingyu
authors.initials: Q
authors.lastname: Wu
mesh_terms: D051722:ADAM Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D000072197:ADAM10 Protein; D053829:Amyloid Precursor Protein Secretases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D000818:Animals; D057809:HEK293 Cells; D006801:Humans; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D051379:Mice; D009206:Myocardium / Q000201:enzymology*; D032383:Myocytes, Cardiac / Q000201:enzymology*; D017434:Protein Structure, Tertiary; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*
chemical_list: D008565:Membrane Proteins; D053829:Amyloid Precursor Protein Secretases; C119812:CORIN protein, human; C485617:Corin protein, mouse; D012697:Serine Endopeptidases; D051722:ADAM Proteins; D000072197:ADAM10 Protein; C491236:ADAM10 protein, human; C491234:Adam10 protein, mouse