Regulation of the Matriptase-Prostasin Cell Surface Proteolytic Cascade by Hepatocyte Growth Factor Activator Inhibitor-1 during Epidermal Differentiation
Regulation of the Matriptase-Prostasin Cell Surface Proteolytic Cascade by Hepatocyte Growth Factor Activator Inhibitor-1 during Epidermal Differentiation
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DOI：
10.1074/jbc.m110.150367
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发表时间：
2010-10-08
影响因子：
4.8
通讯作者：
Lin, Chen-Yong
中科院分区：
文献类型：
--
作者：
Chen, Ya-Wen;Wang, Jehng-Kang;Lin, Chen-Yong
基质酶是一种膜系丝氨酸蛋白酶，在表皮分化和屏障功能中起重要作用，主要是通过激活前列腺蛋白酶介导的，前列腺蛋白酶是一种糖基磷脂酰肌醇锚定的丝氨酸蛋白酶。基质酶活性受其抑制剂肝细胞生长因子激活因子抑制剂-1 （HAI-1）的严格调控，因此游离的活性基质酶只能短暂地作用于其底物。在目前的研究中，我们提供了证据，证明基质酶是如何在HAI-1的严格控制下激活前列腺素的。当在皮肤器官型培养模型中诱导原代人角质形成细胞分化时，基质酶和前列腺蛋白酶都被HAI-1组成性激活，然后被抑制。这些过程也发生在HaCaT人角质形成细胞中，当基质酶被暴露在pH 6.0的缓冲液中诱导激活时。利用这种酸诱导的激活系统，我们证明了前列腺素的激活可以通过基质酶的敲除和氯化钠阻断基质酶的激活来抑制，这表明在该系统中前列腺素的激活依赖于基质酶。动力学研究进一步表明基质酶的自激活时间、前列腺蛋白酶的激活时间以及HAI-1结合对这两种酶的抑制是密切相关的。这些数据表明，在表皮分化过程中，基质蛋白酶-前列腺蛋白酶蛋白水解级联受到两种机制的严格调控：1)前列腺蛋白酶激活与基质蛋白酶自身激活暂时耦合；2)HAI-1快速抑制活性基质蛋白酶和活性前列腺蛋白酶，导致活性基质蛋白酶和活性前列腺蛋白酶都有极短的时间窗口作用于其底物。
Matriptase, a membrane-tethered serine protease, plays essential roles in epidermal differentiation and barrier function, largely mediated via its activation of prostasin, a glycosylphosphatidylinositol-anchored serine protease. Matriptase activity is tightly regulated by its inhibitor hepatocyte growth factor activator inhibitor-1 (HAI-1) such that free active matriptase is only briefly available to act on its substrates. In the current study we provide evidence for how matriptase activates prostasin under this tight control by HAI-1. When primary human keratinocytes are induced to differentiate in a skin organotypic culture model, both matriptase and prostasin are constitutively activated and then inhibited by HAI-1. These processes also occur in HaCaT human keratinocytes when matriptase activation is induced by exposure of the cells to a pH 6.0 buffer. Using this acid-inducible activation system we demonstrate that prostatin activation is suppressed by matriptase knockdown and by blocking matriptase activation with sodium chloride, suggesting that prostatin activation is dependent on matriptase in this system. Kinetics studies further reveal that the timing of autoactivation of matriptase, prostasin activation, and inhibition of both enzymes by HAI-1 binding are closely correlated. These data suggest that, during epidermal differentiation, the matriptase-prostasin proteolytic cascade is tightly regulated by two mechanisms: 1) prostasin activation temporally coupled to matriptase autoactivation and 2) HAI-1 rapidly inhibiting not only active matriptase but also active prostasin, resulting in an extremely brief window of opportunity for both active matriptase and active prostasin to act on their substrates.