Isolation of phosphatidylethanolamine as a solitary cofactor for prion formation in the absence of nucleic acids
Isolation of phosphatidylethanolamine as a solitary cofactor for prion formation in the absence of nucleic acids
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DOI：
10.1073/pnas.1204498109
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发表时间：
2012-05-29
影响因子：
11.1
通讯作者：
Supattapone, Surachai
中科院分区：
文献类型：
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作者：
Deleault, Nathan R.;Piro, Justin R.;Supattapone, Surachai
含有哺乳动物朊病毒蛋白（PrPSc）的致病构象体的感染性朊病毒可以从正常构象体（PrPC）与RNA和脂质分子的混合物重新产生。最近的重建研究表明，核酸是不需要的小鼠朊病毒在体外繁殖，这表明存在一个替代朊病毒繁殖辅因子在脑组织中。然而，这种独特的辅因子的身份和功能特性是未知的。在这里，我们表明，通过纯化和重建的分子负责的抗核酸酶的辅因子的活动在大脑中是内源性磷脂酰乙醇胺（PE）。单独的合成PE促进纯化的重组（rec）PrP底物转化为感染性recPrP（Sc）分子。其他磷脂，包括磷脂酰胆碱、磷脂酰丝氨酸、磷脂酰肌醇和磷脂酰甘油，在不存在RNA的情况下不能促进recPrP（Sc）形成。PE促进了来自所有四种不同动物物种（包括小鼠）的PrPSc分子的繁殖，这表明与RNA不同，PE是体外PrPSc形成的混杂辅因子。磷脂酶处理废除了脑匀浆重建小鼠和仓鼠PrPSc分子的繁殖能力。我们的研究结果确定了一个单一的内源性辅因子能够促进形成朊病毒从多个物种在没有核酸或其他聚阴离子。
Infectious prions containing the pathogenic conformer of the mammalian prion protein (PrPSc) can be produced de novo from a mixture of the normal conformer (PrPC) with RNA and lipid molecules. Recent reconstitution studies indicate that nucleic acids are not required for the propagation of mouse prions in vitro, suggesting the existence of an alternative prion propagation cofactor in brain tissue. However, the identity and functional properties of this unique cofactor are unknown. Here, we show by purification and reconstitution that the molecule responsible for the nuclease-resistant cofactor activity in brain is endogenous phosphatidylethanolamine (PE). Synthetic PE alone facilitates conversion of purified recombinant (rec)PrP substrate into infectious recPrP(Sc) molecules. Other phospholipids, including phosphatidylcholine, phosphatidylserine, phosphatidylinositol, and phosphatidylglycerol, were unable to facilitate recPrP(Sc) formation in the absence of RNA. PE facilitated the propagation of PrPSc molecules derived from all four different animal species tested including mouse, suggesting that unlike RNA, PE is a promiscuous cofactor for PrPSc formation in vitro. Phospholipase treatment abolished the ability of brain homogenate to reconstitute the propagation of both mouse and hamster PrPSc molecules. Our results identify a single endogenous cofactor able to facilitate the formation of prions from multiple species in the absence of nucleic acids or other polyanions.