A furin-like convertase mediates propeptide cleavage of BACE, the Alzheimer's β-secretase
A furin-like convertase mediates propeptide cleavage of BACE, the Alzheimer's β-secretase
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DOI：
10.1074/jbc.m005339200
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发表时间：
2000-12-01
影响因子：
4.8
通讯作者：
Vassar, R
中科院分区：
文献类型：
--
作者：
Bennett, BD;Denis, P;Vassar, R
新型跨膜天冬氨酸蛋白酶BACE(Beta-Site APP裂解酶)是一种分解淀粉样前体蛋白以启动β-淀粉样蛋白形成的β-分泌酶。因此，种族是治疗阿尔茨海默病的主要治疗目标。BACE和其他天冬氨酸蛋白酶一样，有一个前肽结构域被移除以形成成熟的酶。RACE前肽发生在RLPR向下箭头E的序列上，这是一个潜在的呋喃类识别基序。在这里，我们探索了呋喃在BACE前肽结构域处理中的作用。BACE前肽在细胞中的切割似乎不是自动催化的，因为BACE的D93A失活突变体仍然被适当地切割。BACE和呋喃在高尔基体内共定位，前肽的裂解被布雷菲尔丁A和莫能菌素抑制，这两种药物破坏了通过高尔基体的运输。用钙离子载体A23187处理细胞，导致抑制包括Furin在内的钙依赖的蛋白水解酶，或转染有效的Furin抑制剂α(1)-抗胰蛋白酶变异体α(1)-PDX，可显著减少RACE前肽的切割。此外，在缺乏Furin的LoVo细胞系中，BACE前肽不被加工；然而，在Furin转染后，加工被恢复。最后，重组可溶性RACE与重组呋喃的体外消化仅在已建立的E46位点处完全切割。综上所述，我们的结果强烈表明，Furin，或一种类似Furin的前蛋白转换酶，负责裂解RACE前肽域形成成熟的酶。
The novel transmembrane aspartic protease BACE (for Beta-site APP Cleaving Enzyme) is the beta -secretase that cleaves amyloid precursor protein to initiate beta -amyloid formation. As such, RACE is a prime therapeutic target for the treatment of Alzheimer's disease. BACE, like other aspartic proteases, has a propeptide domain that is removed to form the mature enzyme. RACE propeptide cleavage occurs at the sequence RLPR down arrow E, a potential furin recognition motif. Here, we explore the role of furin in BACE propeptide domain processing. BACE propeptide cleavage in cells does not appear to be autocatalytic, since an inactive D93A mutant of BACE is still cleaved appropriately. BACE and furin co-localize within the Golgis apparatus, and propeptide cleavage is inhibited by brefeldin A and monensin, drugs that disrupt trafficking through the Golgi. Treatment of cells with the calcium ionophore A23187, leading to inhibition of calcium-dependent proteases including furin, or transfection with the alpha (1)-antitrypsin variant alpha (1)-PDX, a potent furin inhibitor, dramatically reduces cleavage of the RACE propeptide. Moreover, the BACE propeptide is not processed in the furin-deficient LoVo cell line; however, processing is restored upon furin transfection. Finally, in vitro digestion of recombinant soluble RACE with recombinant furin results in complete cleavage only at the established E46 site. Taken together, our results strongly suggest that furin, or a furin-like proprotein convertase, is responsible for cleaving the RACE propeptide domain to form the mature enzyme.