Corin Mutation R539C from Hypertensive Patients Impairs Zymogen Activation and Generates an Inactive Alternative Ectodomain Fragment
Corin Mutation R539C from Hypertensive Patients Impairs Zymogen Activation and Generates an Inactive Alternative Ectodomain Fragment
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高血压患者的 Corin 突变 R539C 损害酶原激活并生成无活性的替代胞外域片段
DOI：
10.1074/jbc.m112.411512
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发表时间：
2013-03-15
影响因子：
4.8
通讯作者：
Wu, Qingyu
中科院分区：
文献类型：
--
作者：
Dong, Ningzheng;Fang, Chaodong;Wu, Qingyu
Corin是一种心脏跨膜丝氨酸蛋白酶，通过激活利钠肽来调节血压。Corin变异与患有高血压和心脏病的非裔美国人有关。在这里，我们报告了在一个高血压患者家族中发现的Corin基因外显子12的新突变。该突变导致了Corin前肽区Fz2(Frizzled2)区域的R539C替换。我们在HEK293细胞中表达并鉴定了Corin R539C突变体。Western印迹分析表明，R539C突变不改变Corin在转基因细胞中的表达，但削弱了Corin酶原的激活。在心房利钠肽加工试验中，Corin突变体的活性降低，并对野生型Corin表现出显性-负性效应。此外，R539C突变改变了Corin胞外结构域的脱落，产生了一种类似于75 kDa片段的替代片段，该片段在生物学上是不活跃的。利用蛋白酶抑制剂和无催化活性的Corin突变体S985A，我们证明了Corin自身切割产生了类似于75 kDa的片段。我们通过替换Corin前肽中的单或双Arg残基构建了一系列突变体，并确定Fz2结构域中的Arg-530是替代的自切位点。我们的结果表明，在高血压患者中发现的Corin突变R539C会损害Corin酶原的激活，并导致另一种降低Corin活性的自切作用。这些数据支持人类Corin基因突变导致Corin活性受损可能是高血压的潜在机制。
Corin is a cardiac transmembrane serine protease that regulates blood pressure by activating natriuretic peptides. Corin variants have been associated with African Americans with hypertension and heart disease. Here, we report a new mutation in exon 12 of the CORIN gene identified in a family of patients with hypertension. The mutation resulted in R539C substitution in the Fz2 (Frizzled-2) domain of the corin propeptide region. We expressed and characterized the corin R539C mutant in HEK293 cells. As determined by Western blot analysis, the R539C mutation did not alter corin expression in transfected cells but impaired corin zymogen activation. In a proatrial natriuretic peptide processing assay, the corin mutant had reduced activity and exhibited a dominant-negative effect on wild-type corin. In addition, the R539C mutation altered corin ectodomain shedding, producing an alternative similar to 75-kDa fragment that was biologically inactive. Using protease inhibitors and the catalytically inactive corin mutant S985A, we showed that the similar to 75-kDa fragment was generated by corin autocleavage. We constructed a series of mutants by replacing single or double Arg residues in the corin propeptide and identified Arg-530 in the Fz2 domain as the alternative autocleavage site. Our results show that the corin mutation R539C identified in hypertensive patients impairs corin zymogen activation and causes an alternative autocleavage that reduces corin activity. These data support that human CORIN gene mutations causing impaired corin activity may be an underlying mechanism in hypertension.