Corin Variant Associated With Hypertension and Cardiac Hypertrophy Exhibits Impaired Zymogen Activation and Natriuretic Peptide Processing Activity

Abstract

Abstract-Corin is a cardiac serine protease that acts as the pro-atrial natriuretic peptide (ANP) convertase. Recently, 2 single-nucleotide polymorphisms (SNPs) (T555I and Q568P) in the human corin gene have been identified in genetic epidemiological studies. The minor I555/P568 allele, which is more common in African Americans, is associated with hypertension and cardiac hypertrophy. In this study, we examined the effect of T555I and Q568P amino acid substitutions on corin function. We found that corin frizzled-like domain 2, where T555I/Q568P substitutions occur, was required for efficient pro-ANP processing in functional assays. Mutant corin lacking this domain had 30Ϯ5% (PϽ0.01) activity compared to that of wild type. Similarly, corin variant T555I/Q568P had a reduced (38Ϯ7%, PϽ0.01) pro-ANP processing activity compared to that of wild type. The variant also exhibited a low activity (44Ϯ15%, PϽ0.05) in processing pro-brain natriuretic peptide (BNP). We next examined the biochemical basis for the loss of activity in T555I/Q568P variant and found that the zymogen activation of the corin variant was impaired significantly, as indicated by the absence of the activated protease domain fragment. This finding was confirmed in human embryonic kidney (HEK)293 cells and murine HL-1 cardiomyocytes. Thus, our results show that the corin gene SNPs associated with hypertension and cardiac hypertrophy impair corin zymogen activation and natriuretic peptide processing activity. Our data suggest that corin deficiency may be an important mechanism in hypertensive and heart diseases. (Circ Res. 2008;103:502-508.)Key Words: natriuretic peptides Ⅲ genetic variants Ⅲ protease A trial natriuretic peptide (ANP) is a cardiac hormone that regulates blood pressure and salt-water balance. 1-3 The ANP pathway also has an antihypertrophic function in the heart, which is independent of its systemic action on blood pressure. 4 -7 Corin is a cardiac enzyme of the type II transmembrane serine protease family. 8 -10 It has a cytoplasmic tail and a transmembrane domain near the N terminus. In its extracellular region, there are 2 frizzled-like domains, 8 LDL receptor (LDLR) repeats, a scavenger receptor-like domain, and a C-terminal trypsin-like protease domain. Corin converts pro-ANP into active ANP. 11,12 In mice, corin deficiency prevented pro-ANP activation, 13 demonstrating that corin is the physiological pro-ANP convertase. Corin-null mice developed hypertension and cardiac hypertrophy. 13 Corin also cleaved pro-brain natriuretic peptide (BNP) in vitro, although the cleavage was less efficient than that for pro-ANP. 12 Hypertension is the most common cardiovascular disease, and its prevalence is even higher in African Americans, but the underlying mechanism is unclear. 14,15 Recently, 2 nonsynonymous and nonconservative single-nucleotide polymorphisms (SNPs) (T555I and Q568P) are found in the human corin gene. These 2 SNPs are in complete linkage disequilibrium in the population and, as a result, are colocalized in a minor allele (I555...

Processing of Pro–B-Type Natriuretic Peptide: Furin and Corin as Candidate Convertases2

“…In cell-based experiments, corin has been shown to be a specific enzyme responsible for processing of the A-type natriuretic peptide precursor (17,18 ). Corin has also been suggested to be responsible for proBNP processing (19 ), but its potential involvement in this process has not been supported by convincing experimental data. Thus, the role of both candidate enzymes, furin and corin, in proBNP processing should be validated.…”

Matriptase-2 (TMPRSS6): a proteolytic regulator of iron homeostasis

“…63,64 Biochemically, the mutations cause reduced pro-ANP activation due to an impaired corin zymogen conversion. 65 Interestingly, the frequency of the mutant allele within the Afro-American population is three times higher than in the American Caucasian population, potentially correlating to the increased risk of hypertension and heart disease in Afro-Americans. 63 The matriptase sub-family contains the highly similar matriptase, matriptase-2, 22,66 matriptase-3 67 and the mosaic poly-protease, polyserase-1.…”

Corin Mutations K317E and S472G from Preeclamptic Patients Alert Zymogen Activation and Cell Surface Targeting

“…In functional studies, both T555I/Q568P and R539C proteins were shown on the cell surface. However, corin T555I/Q568P remained in an inactive zymogen form, whereas corin R539C was activated but quickly inactivated by autocleavage (19,51). In this study, corin K317E was found on the cell surface with impaired zymogen activation, whereas corin S472G was found retained in the ER.…”