Novel processing of β-amyloid precursor protein catalyzed by membrane type 1 matrix metalloproteinase releases a fragment lacking the inhibitor domain against gelatinase A
Novel processing of β-amyloid precursor protein catalyzed by membrane type 1 matrix metalloproteinase releases a fragment lacking the inhibitor domain against gelatinase A
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DOI：
10.1021/bi020643m
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发表时间：
2003-06-03
期刊：
影响因子：
2.9
通讯作者：
Miyazaki, K
中科院分区：
文献类型：
--
作者：
Higashi, S;Miyazaki, K
在各种哺乳动物细胞系中，β-淀粉样前体蛋白 (APP) 经过蛋白水解加工，以可溶性 APP (sAPP) 的形式释放其 NH2 末端胞外结构域，其中含有明胶酶 A 的抑制剂结构域。为了研究 SAPP 在明胶酶 A 活性调节中的作用，我们检查了原明胶酶 A 的激活与 APP 加工之间的相关性。我们发现用伴刀豆球蛋白 A 刺激 HT1080 纤维肉瘤细胞会激活内源性明胶酶 A 并导致 APP 的新加工，从而将 COOH 末端截短形式的 sAPP (sAPPtrc) 释放到培养基中。反向酶谱分析表明 sAPPtrc 缺乏对明胶酶 A 的抑制活性。在各种金属蛋白酶抑制剂存在下对 sAPPtrc 产生的分析表明，膜 1 型基质金属蛋白酶 (MT1-MMP)（原明胶酶 A 的激活剂）最有可能是 sAPPtrc 产生的原因。当伴刀豆球蛋白 A 刺激的 HT 1080 细胞在抑制 MT1-MMP 活性的条件下培养时，sAPP 和 APP 与细胞沉积的细胞外基质相关，而基质中的这些明胶酶 A 抑制剂在 MT1-MMP 活性发挥后被 sAPPtrc 取代。总而言之，这些数据支持这样一个模型，其中 MT1-MMP 催化的 sAPPtrc 释放导致细胞外基质相关明胶酶 A 抑制剂 SAPP 的减少，从而使明胶酶 A 仅在其激活剂 MT1-MMP 附近发挥蛋白水解活性是可行的。
In various mammalian cell lines, beta-amyloid precursor protein (APP) is proteolytically processed to release its NH2-terminal extracellular domain as a soluble APP (sAPP) that contains the inhibitor domain against gelatinase A. To investigate roles of SAPP in the regulation of gelatinase A activity, we examined the correlation between the activation of progelatinase A and processing of APP. We found that stimulation of HT1080 fibrosarcoma cells with concanavalin A led to an activation of endogenous progelatinase A and to a novel processing of APP, which releases a COOH-terminally truncated form of sAPP (sAPPtrc) into the culture medium. Reverse zymographic analysis showed that sAPPtrc lacked an inhibitory activity against gelatinase A. Analyses of production of sAPPtrc in the presence of various metalloproteinase inhibitors showed that membrane type 1 matrix metalloproteinase (MT1-MMP), an activator of progelatinase A, is most likely responsible for the production of sAPPtrc. When the concanavalin A-stimulated HT 1080 cells were cultured in the condition that inhibited MT1-MMP activity, sAPP and APP were associated with the extracellular matrix deposited by the cells, whereas these gelatinase A inhibitors in the matrix were displaced by sAPPtrc after exertion of MT1-MMP activity. Taken together, these data support a model in which MT1-MMP-catalyzed release of sAPPtrc leads to reduction of the extracellular matrix-associated gelatinase A inhibitor, SAPP, thus making it feasible for gelatinase A to exert proteolytic activity only near its activator, MT1-MMP.