THE ROLE OF COPPER IN PRION PROTEIN BIOLOGY

描述(摘自申请者的摘要)：Pron疾病 一种神经退行性疾病，由一种蛋白的构象变化引起 一种极不寻常的膜糖蛋白，称为PrP(普里恩蛋白)。这 分子转换将正常版本的蛋白质(PrPc)转化为 构成病毒主要成分的致病形式(PrPsc) 一种史无前例的缺乏核酸的传染性粒子(Pron)。 尽管现在有大量关于PrPsc在 发病过程中，对正常的、生理性的了解相对较少 PrPC的功能。除了其内在的生物学意义，识别出 PrPc的功能可能对了解其发病机制具有重要意义。 Prion病，因为已有研究表明，这种功能的损害是一种 转化为PrPsc的结果可能解释了这种疾病的一些特征 表型。 最近出现了几条证据，表明PrPc可能在 在必需的微量金属的细胞新陈代谢中起着重要作用， 铜。最令人信服的结果是铜与低微摩尔结合 对PrPc亲和力，PrP基因缺失小鼠大脑的膜组分显示 正常离子铜含量的5%，神经元铜锌 这些小鼠的超氧化物歧化酶的酶活性较低， 与正常小鼠的酶相比，含有较少的放射性铜。在……里面 此外，我自己的实验室最近显示，铜离子迅速和 显著改变PrPc在培养神经元中的细胞运输。已被占用 总而言之，这些发现构成了正常情况下最实质性的线索 PrPc的功能在蛋白质被发现后的15年里出现。 他们提出了PrPc可能在细胞通路中发挥作用的假设 负责铜离子的吸收、输送或排泄。结果还包括 提高了在普里昂过程中铜代谢发生改变的可能性 疾病，以及铜水平的操纵可能有助于治疗 失调症。 在本应用程序中，我们将通过(1)分析 PrPc与铜在细胞和生化水平上的相互作用 哺乳动物细胞，(2)通过使用酵母来阐明酿酒酵母的作用 铜交易中的PrPC，(3)通过表征铜之间的相互作用 和疾病特异性异构体PrPsc，以及(4)通过使用PET成像 放射性铜在活体小鼠体内的分布。

DESCRIPTION (From the applicant's abstract): Prion diseases are neurodegenerative disorders that result from changes in the conformation of a single, highly unusual membrane glycoprotein called PrP (prion protein). This molecular transition converts a normal version of the protein (PrPc) into a pathogenic form (PrPsc) that constitutes the major component of an unprecedented type of infectious particle (prion) devoid of nucleic acid. Although a wealth of information is now available about the role of PrPsc in the disease process, relatively little is known about the normal, physiological function of PrPc. Aside from its intrinsic biological interest, identifying the function of PrPc is likely to be important in understanding the pathogenesis of prion disease, as it has been suggested that impairment of this function as a result of conversion to PrPsc may explain some features of the disease phenotype. Several lines of evidence have emerged recently suggesting that PrPc may play an important role in the cellular metabolism of the essential trace metal, copper. The most compelling results are that copper binds with low micromolar affinity to PrPc, that membrane fractions from the brains of PrP-null mice show 5 percent of the normal content of ionic copper, and that neuronal Cu-Zn superoxide dismutase from these mice is less enzymatically active and incorporates less radioactive copper than the enzyme from normal mice. In addition, my own laboratory has recently shown that copper ions rapidly and dramatically alter the cellular trafficking of PrPc in cultured neurons. Taken together, these findings constitute the most substantial clues to the normal function of PrPc to emerge in the 15 years since the protein was discovered. They suggest the hypothesis that PrPc may function in cellular pathways responsible for uptake delivery, or excretion of copper ions. The results also raise the possibility that copper metabolism may be altered during prion diseases, and that manipulation of copper levels may be useful in treatment of the disorders. In this application, we will investigate these ideas by (1) analyzing the interactions between PrPc and copper at the cellular and biochemical levels in mammalian cells, (2) by using the yeast S. cerevisiae to elucidate the role of PrPc in copper trafficking, (3) by characterizing the interplay between copper and the disease-specific isoform PrPsc, and (4) by using PET to image the distribution of radioactive copper in living mice.