Pathway complexity of prion protein assembly into amyloid
Pathway complexity of prion protein assembly into amyloid
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DOI：
10.1074/jbc.m111402200
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发表时间：
2002-06-14
影响因子：
4.8
通讯作者：
Cohen, FE
中科院分区：
文献类型：
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作者：
Baskakov, IV;Legname, G;Cohen, FE
在体内，在病理条件下，PrPC(残基23-231)的正常细胞形式错误折叠为致病亚型PrPSc，一种富含β的聚集性致病多聚体。PrPSc的蛋白酶K消化导致一个抗蛋白水解性核心PrP27-30(残基90-231)，它可以形成淀粉样纤维。为了研究体外淀粉样蛋白形成的动力学途径，我们使用了与PrPSc的蛋白酶K抗性核心相对应的未糖化的重组PrP，发现它可以采用两种非天然的异常异构体，一种是β-寡聚体，另一种是淀粉样原纤维。几条动力学数据表明，β-寡聚体不在形成淀粉样蛋白的途径上。形成β-寡聚体或淀粉样蛋白的偏好可以由实验条件决定，酸性pH与胞内囊泡相似，有利于形成β-寡聚体，中性pH有利于淀粉样蛋白。虽然这两种异常异构体都有很高的β-折叠含量，并结合了1-苯基-8-萘磺酸盐，但它们在结构上是不同的。多种途径的错误折叠和不同的富含β-折叠的异常异构体的形成可能解释了体外复性PrPSc的困难，需要PrPSc模板，以及疾病表现和神经病理的显著差异。
In vivo under pathological conditions, the normal cellular form of the prion protein, PrPC (residues 23-231), misfolds to the pathogenic isoform PrPSc, a beta-rich aggregated pathogenic multimer. Proteinase K digestion of PrPSc leads to a proteolytically resistant core, PrP 27-30 (residues 90-231), that can form amyloid fibrils. To study the kinetic pathways of amyloid formation in vitro, we used unglycosylated recombinant PrP corresponding to the proteinase K-resistant core of PrPSc and found that it can adopt two non-native abnormal isoforms, a beta-oligomer and an amyloid fibril. Several lines of kinetic data suggest that the beta-oligomer is not on the pathway to amyloid formation. The preferences for forming either a beta-oligomer or amyloid can be dictated by experimental conditions, with acidic pH similar to that seen in endocytic vesicles favoring the beta-oligomer and neutral pH favoring amyloid. Although both abnormal isoforms have high beta-sheet content and bind 1-anilinonaphthalene-8-sulfonate, they are dissimilar structurally. Multiple pathways of misfolding and the formation of distinct beta-sheet-rich abnormal isoforms may explain the difficulties in refolding PrPSc in vitro, the need for a PrPSc template, and the significant variation in disease presentation and neuropathology.