Harmey J H, Doyle D, Brown V, Rogers M S
Department of Zoology, University College Dublin, Belfield, Ireland.
Biochem Biophys Res Commun. 1995 May 25;210(3):753-9. doi: 10.1006/bbrc.1995.1723.
A major component of the infectious particle causing spongiform encephalopathies or prion diseases is an aberrant isoform (PrPSc) of a glycosyl-phosphatidylinositol (GPI)-anchored cell surface protein, PrPC. The cellular processes involved in the formation of PrPSc are unclear but involve the internalization of PrPC prior to conversion. Here, we demonstrate that PrPC is associated with caveolin, a structural protein component of caveolae. We show that PrPC and caveolin share similar detergent characteristics and copurify in linear sucrose gradients. PrPC was protected from proteinase K digestion in the caveolin fraction but solubilizing the caveolae prior to proteinase K digestion rendered PrPC susceptible to proteinase K digestion. Our results indicate a physical association between PrPC and caveolin in N2a cells. The implication of these results in relation to prion biogenesis is discussed.
导致海绵状脑病或朊病毒疾病的感染性颗粒的一个主要成分是糖基磷脂酰肌醇（GPI）锚定的细胞表面蛋白PrPC的异常异构体（PrPSc）。PrPSc形成过程中涉及的细胞过程尚不清楚，但在转化之前涉及PrPC的内化。在这里，我们证明PrPC与小窝蛋白（一种小窝的结构蛋白成分）相关联。我们表明PrPC和小窝蛋白具有相似的去污剂特性，并在线性蔗糖梯度中共纯化。在小窝蛋白组分中，PrPC免受蛋白酶K消化，但在蛋白酶K消化之前溶解小窝会使PrPC易受蛋白酶K消化。我们的结果表明N2a细胞中PrPC和小窝蛋白之间存在物理关联。讨论了这些结果与朊病毒生物发生的关系。
