Laboratory of Immunology, College of Veterinary Medicine, Seoul National University, Seoul 151-742, Korea.
Biochem Biophys Res Commun. 2013 Mar 15;432(3):539-44. doi: 10.1016/j.bbrc.2013.02.021. Epub 2013 Feb 14.
Iron dyshomeostasis has been observed in prion diseases; however, little is known regarding the contribution of the oxidation state of iron to prion protein (PrP) conversion. In this study, PrP(C)-deficient HpL3-4 cells were exposed to divalent [Fe(II)] or trivalent [Fe(III)] iron, followed by exogenous recombinant PrP (rPrP) treatment. We then analyzed the accumulation of internalized rPrP and its biochemical properties, including its resistance to both proteinase K (PK) digestion and detergent solubility. Fe(III), but not Fe(II), induced the accumulation of internalized rPrP, which was partially converted to detergent-insoluble and PK-resistant PrP (PrP(res)). The Fe(III)-induced PrP(res) generation required an intact cell structure, and it was hindered by U18666A, an inhibitor of vesicular trafficking, but not by NH4Cl, an inhibitor of endolysosomal acidification. These observations implicated that the Fe(III)-mediated PrP(res) conversion likely occurs during endosomal vesicular trafficking rather than in the acidic environment of lysosomes.
铁动态平衡已在朊病毒病中观察到；然而，对于铁的氧化态对朊病毒蛋白（PrP）转化的贡献知之甚少。在这项研究中，将缺乏 PrP(C) 的 HpL3-4 细胞暴露于二价[Fe(II)]或三价[Fe(III)]铁，然后用外源性重组 PrP（rPrP）处理。然后，我们分析了内化 rPrP 的积累及其生化特性，包括其对蛋白酶 K（PK）消化和去污剂溶解度的抗性。Fe(III)，而不是 Fe(II)，诱导内化 rPrP 的积累，其部分转化为去污剂不溶性和 PK 抗性 PrP（PrP(res)）。Fe(III)诱导的 PrP(res)生成需要完整的细胞结构，它被囊泡运输抑制剂 U18666A 抑制，但不受溶酶体酸化抑制剂氯化铵的抑制。这些观察结果表明，Fe(III)介导的 PrP(res)转化可能发生在内体囊泡运输过程中，而不是在溶酶体的酸性环境中。
