CHLOROQUINE INHIBITS INTRACELLULAR DEGRADATION BUT NOT SECRETION OF ALZHEIMER BETA/A4 AMYLOID PRECURSOR PROTEIN
CHLOROQUINE INHIBITS INTRACELLULAR DEGRADATION BUT NOT SECRETION OF ALZHEIMER BETA/A4 AMYLOID PRECURSOR PROTEIN
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DOI：
10.1073/pnas.89.6.2252
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发表时间：
1992-03-15
影响因子：
11.1
通讯作者：
GREENGARD, P
中科院分区：
文献类型：
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作者：
CAPORASO, GL;GANDY, SE;GREENGARD, P
阿尔茨海默病β/A4淀粉样前体蛋白（APP）的代谢命运包括淀粉样蛋白内蛋白水解，导致分泌的N-末端和细胞相关的C-末端片段的产生。进行这种处理的蜂窝站点是未知的。我们研究了代谢标记的PC 12细胞中APP加工的途径。促溶酶体药物氯喹对APP全蛋白的降解有抑制作用。此外，恢复正常的淀粉样蛋白内切割产生的C-末端片段显着增加氯喹的存在下，表明进一步降解的C-末端片段被抑制。氯喹对APP成熟（N-和O-糖基化和酪氨酸硫酸化）或分泌几乎没有影响。用莫能菌素（其抑制远端高尔基体功能）或布雷菲德菌素A（其导致高尔基体再吸收到内质网中并使trans-Golgi网络与内体系统融合）处理阻止了正常的APP成熟并消除了APP分泌和C-末端片段的恢复，表明完整的高尔基体功能对于APP成熟和加工是必要的。我们的研究结果表明，相当大比例的APP降解在细胞内的酸性区室，但耦合APP裂解/分泌事件发生在氯喹不敏感的区室。观察结果与APP的运输和蛋白水解的多个细胞途径的存在是一致的。
The metabolic fate of the Alzheimer beta/A4 amyloid precursor protein (APP) includes intraamyloid proteolysis that leads to the production of secreted N-terminal and cell-associated C-terminal fragments. The cellular sites at which this processing occurs are not known. We have examined the route of APP processing in metabolically labeled PC12 cells. The lysosomotropic drug chloroquine exerted inhibitory effects on the degradation of mature APP holoprotein. In addition, recovery of a C-terminal fragment resulting from normal intraamyloid cleavage was significantly increased in the presence of chloroquine, suggesting that further degradation of the C-terminal fragment was inhibited. Chloroquine had virtually no effect on APP maturation (N- and O-glycosylation and tyrosine sulfation) or secretion. Treatment with either monensin (which inhibits distal Golgi function) or brefeldin A (which causes resorption of the Golgi into the endoplasmic reticulum and fusion of the trans-Golgi network with the endosomal system) prevented normal APP maturation and abolished APP secretion and recovery of C-terminal fragments, indicating that intact Golgi function is necessary for APP maturation and processing. Our results suggest that a substantial proportion of APP is degraded in an intracellular acidic compartment but that the coupled APP cleavage/secretion event occurs in a chloroquine-insensitive compartment. The observations are consistent with the existence of multiple cellular routes for the trafficking and proteolysis of APP.