AN INCREASED PERCENTAGE OF LONG AMYLOID-BETA PROTEIN SECRETED BY FAMILIAL AMYLOID-BETA PROTEIN-PRECURSOR (BETA-APP(717)) MUTANTS
AN INCREASED PERCENTAGE OF LONG AMYLOID-BETA PROTEIN SECRETED BY FAMILIAL AMYLOID-BETA PROTEIN-PRECURSOR (BETA-APP(717)) MUTANTS
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DOI：
10.1126/science.8191290
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发表时间：
1994-05-27
期刊：
影响因子：
56.9
通讯作者：
YOUNKIN, SG
中科院分区：
文献类型：
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作者：
SUZUKI, N;CHEUNG, TT;YOUNKIN, SG
淀粉样β蛋白前体（β APP）的正常加工导致可溶性4千道尔顿蛋白质的分泌，所述可溶性4千道尔顿蛋白质基本上与在阿尔茨海默病中形成不溶性纤维状沉积物的淀粉样β蛋白（A β）相同。用表达野生型β APP或与家族性阿尔茨海默病相关的β APP（717）突变体的构建体转染的人神经母细胞瘤（M17）细胞通过以下方式进行比较：（i）从条件培养基中分离代谢标记的4千道尔顿A β，用溴化氰消化，并分析释放的羧基末端肽，或（ii）用区分Ap（1-40）和较长的AP（1- 42）的夹心酶联免疫吸附测定法分析条件培养基中的A β。两种方法都证明了从野生型β APP释放的4千道尔顿Ap主要但不完全是AP（1-40）。β APP（717）突变位于A β（43）的三个羧基残基上，始终导致产生的较长A β的百分比增加1.5至1.9倍。长A β（例如，A β（1-42））比A β（1-40）更快地形成不溶性淀粉样纤维。因此，β APP（717）突变体可能会导致阿尔茨海默病，因为它们分泌增加量的长A β，从而促进淀粉样蛋白沉积。
Normal processing of the amyloid beta protein precursor (beta APP) results in secretion of a soluble 4-kilodalton protein essentially identical to the amyloid beta protein (A beta) that forms insoluble fibrillar deposits in Alzheimer's disease. Human neuroblastoma (M17) cells transfected with constructs expressing wild-type beta APP or the beta APP(717) mutants linked to familial Alzheimer's disease were compared by (i) isolation of metabolically labeled 4-kilodalton A beta from conditioned medium, digestion with cyanogen bromide, and analysis of the carboxyl-terminal peptides released, or (ii) analysis of the A beta in conditioned medium with sandwich enzyme-linked immunosorbent assays that discriminate Ap(1-40) from the longer AP(1-42). Both methods demonstrated that the 4-kilodalton Ap released from wild-type beta APP is primarily but not exclusively AP(1-40). The beta APP(717) mutations, which are located th ree residues carboxyl to A beta(43), consistently caused a 1.5- to 1.9-fold increase in the percentage of longer A beta generated. Long A beta (for example, A beta(1-42)) forms insoluble amyloid fibrils more rapidly than Ap(1-40). Thus, the beta APP(717) mutants may cause Alzheimer's disease because they secrete increased amounts of long A beta, thereby fostering amyloid deposition.