Role of glycosylation in corin zymogen activation
Role of glycosylation in corin zymogen activation
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DOI：
10.1074/jbc.m703687200
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发表时间：
2007-09-21
影响因子：
4.8
通讯作者：
Wu, Qingyu
中科院分区：
文献类型：
--
作者：
Liao, Xudong;Wang, Wei;Wu, Qingyu
心脏丝氨酸蛋白酶corin是前心钠素转化酶。Corin作为酶原被制备，其通过蛋白水解裂解被激活。已有研究表明，在HEK 293细胞中表达的重组人corin具有生物活性，但未检测到激活的corin片段，表明重组大鼠corin在HEK 293细胞、小鼠HL-1心肌细胞和大鼠乳鼠心肌细胞中被激活。在这些细胞中，活化的corin占总corin分子的一小部分。小分子胰蛋白酶抑制剂，但不抑制基质金属蛋白酶或半胱氨酸蛋白酶的重组大鼠corin的激活，这表明胰蛋白酶样蛋白酶激活corin在这些细胞。糖苷酶消化表明，大鼠和人类corin蛋白含有大量的N-聚糖，但很少的O-聚糖。用衣霉素处理表达大鼠corin的HEK 293细胞可阻止corin活化并抑制其前心钠素加工活性。衣霉素对HL-1细胞内源性corin活性的影响与此相似。改变大鼠corin蛋白酶结构域中两个N-糖基化位点的突变阻止了其在HEK 293和HL-1细胞中的活化。我们的研究结果表明，N-连接的寡糖在corin激活中起着重要作用。
The cardiac serine protease corin is the pro-atrial natriuretic peptide convertase. Corin is made as a zymogen, which is activated by proteolytic cleavage. Previous studies showed that recombinant human corin expressed in HEK 293 cells was biologically active, but activated corin fragments were not detectashowed that recombinant rat corin was activated in HEK 293 cells, murine HL-1 cardiomyocytes, and rat neonatal cardiomyocytes. In these cells, activated corin represented a small fraction of the total corin molecules. The activation of recombinant rat corin was inhibited by small molecule trypsin inhibitors but not inhibitors for matrix metalloproteinases or cysteine proteases, suggesting that a trypsin-like protease activated corin in these cells. Glycosidase digestion showed that rat and human corin proteins contained substantial N-glycans but little O-glycans. Treatment of HEK 293 cells expressing rat corin with tunicamycin prevented corin activation and inhibited its pro-atrial natriuretic peptide processing activity. Similar effects of tunicamycin on endogenous corin activity were found in HL-1 cells. Mutations altering the two N-glycosylation sites in the protease domain of rat corin prevented its activation in HEK 293 and HL-1 cells. Our results indicate that N-linked oligosaccharides play an important role in corin activation.