Acquisition of protease resistance by prion proteins in scrapie-infected cells does not require asparagine-linked glycosylation.
Acquisition of protease resistance by prion proteins in scrapie-infected cells does not require asparagine-linked glycosylation.
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DOI：
10.1073/pnas.87.21.8262
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发表时间：
1990-11
影响因子：
11.1
通讯作者：
A. Taraboulos;M. Rogers;D. Borchelt;M. McKinley;M. Scott;D. Serban;S. Prusiner
中科院分区：
文献类型：
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作者：
A. Taraboulos;M. Rogers;D. Borchelt;M. McKinley;M. Scott;D. Serban;S. Prusiner
PrPSc和PrPc在许多生化和代谢特性上有明显的不同。这些差异背后的结构特征尚不清楚，但它们被认为是翻译后过程的结果。两种PrP亚型都含有复杂类型的寡糖，这增加了天冬酰胺连接糖基化的差异解释了PrPC和PrPSc区别性质的可能性。SCN2A和Schab细胞在培养过程中产生相对分子质量为26-35 kDa的PrP分子和19-29 kDa的抗蛋白酶K核心。当用衣霉素处理细胞时，这种异质性被消除，并观察到26 kDa的单一PrP物种。合成几个小时后，这种蛋白的一部分变得不溶于洗涤剂，并获得了一个抗蛋白酶K的核心，从而显示出PrPSc的两个生化特征。在衣霉素存在下的合成将PrP的抗蛋白酶K核心限制在19 kDa的单一物种。未感染细胞中未发现抗蛋白酶K的PrP。突变的PrP基因在SCN2A细胞中表达缺失两个天冬酰胺连接的糖基化位点，导致19 kDa蛋白酶K抗性PrP分子的合成。我们的结论是，天冬酰胺连接的糖基化不是合成抗蛋白酶K的PrP所必需的，PrPC和PrPSc之间肯定存在与天冬酰胺连接的寡糖无关的结构差异。非糖化PrPSc分子是否与瘙痒病病毒的传染性有关仍有待确定。
The scrapie and cellular isoforms of the prion protein (PrPSc and PrPC) differ strikingly in a number of their biochemical and metabolic properties. The structural features underlying these differences are unknown, but they are thought to result from a posttranslational process. Both PrP isoforms contain complex type oligosaccharides, raising the possibility that differences in the asparagine-linked glycosylation account for the properties that distinguish PrPC and PrPSc. ScN2a and ScHaB cells in culture produce several PrP molecules with relative molecular masses of 26-35 kDa and proteinase K-resistant cores of 19-29 kDa. When the cells were treated with tunicamycin, this heterogeneity was eliminated and a single PrP species of 26 kDa was observed. Several hours after its synthesis, a fraction of this protein became insoluble in detergents and acquired a proteinase K-resistant core, thus displaying two of the biochemical hallmarks of PrPSc. Synthesis in the presence of tunicamycin restricted the proteinase K-resistant cores of PrP to a single species of 19 kDa. No proteinase K-resistant PrP was found in uninfected cells. Expression of a mutated PrP gene lacking both asparagine-linked glycosylation sites in ScN2a cells resulted in the synthesis of 19-kDa proteinase K-resistant PrP molecules. We conclude that asparagine-linked glycosylation is not essential for the synthesis of proteinase K-resistant PrP and that structural differences unrelated to asparagine-linked oligosaccharides must exist between PrPC and PrPSc. Whether unglycosylated PrPSc molecules are associated with scrapie prion infectivity remains to be established.