Fibroinase and its physiological inhibitors involved in the regulation of silk gland development in the silkworm, Bombyx mori
Fibroinase and its physiological inhibitors involved in the regulation of silk gland development in the silkworm, Bombyx mori
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纤维蛋白酶及其生理抑制剂参与家蚕丝腺发育的调节
DOI：
10.1016/j.ibmb.2019.01.003
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发表时间：
2019-03-01
影响因子：
3.8
通讯作者：
Zhao, Ping
中科院分区：
文献类型：
--
作者：
Guo, Pengchao;Wang, Zhan;Zhao, Ping
纤维蛋白酶是一种组织蛋白酶 L 样半胱氨酸蛋白酶，之前在蚕 Bombyx mori 的丝腺中被发现。它在蛹前时期表现出高降解活性，此时丝腺经历细胞凋亡和重塑。在这里，我们重组表达了纤维蛋白酶原并在体外激活它。丝素酶在pH 4.0时表现出最佳水解活性，最适温度约为42℃。发现了一种生理抑制剂——家蚕半胱氨酸蛋白酶抑制剂(BCPI)，对丝素酶表现出较强的抑制活性。抑制反应是由非共价复合物的形成引起的；这与之前报道的 Serpin18 丝素酶抑制模式形成对比。表达谱和免疫定位分析表明，丝素酶通过在特定点降解丝蛋白和丝腺凋亡/重塑来参与丝腺发育。此外，对丝素酶及其抑制剂BCPI和Serpin18的时间表达的比较表明，这些抑制剂通过调节从第五龄到纺丝早期的丝素酶活性参与丝腺发育。这些发现提高了我们对丝腺发育中蛋白酶调节机制及其抑制剂的理解。
Fibroinase, a cathepsin L-like cysteine protease, was previously identified in the silk gland of the silkworm, Bombyx mori. It shows high degradation activity during the pre-pupa period, when the silk gland undergoes apoptosis and remodeling. Here, we recombinantly expressed pro-fibroinase and activated it in vitro. Fibroinase showed optimal hydrolytic activity at pH 4.0 and its optimum temperature was about 42 degrees C. One physiological inhibitor, B. mori cysteine protease inhibitor (BCPI) was found, which showed strong inhibitory activity against fibroinase. The inhibitory reaction was caused by the formation of a non-covalent complex; this is in contrast to a previously reported mode of fibroinase inhibition by Serpin18. Expression profiles and immunolocalization analysis demonstrated that fibroinase was involved in silk gland development by degrading silk proteins and apoptosis/remodeling of silk glands at specific points. Furthermore, the comparison of the temporal expression of fibroinase and its inhibitors, BCPI and Serpin18, indicated that these inhibitors were involved in the silk gland development by regulating the activity of fibroinase from the fifth instar until the early spinning stage. These findings improve our understanding of the mechanism of protease regulation and its inhibitors in silk gland development.