THE ROLE OF COPPER IN PRION PROTEIN BIOLOGY

描述（来自申请人的摘要）：朊病毒疾病是 神经退行性疾病，其是由神经元的构象变化引起的。 一种非常罕见的膜糖蛋白，称为朊病毒蛋白。这 分子转换将正常形式的蛋白质（PrPc）转化为 病原体形式（PrPsc），构成了一种 一种前所未有的缺乏核酸的传染性颗粒（朊病毒）。 虽然现在有大量关于PrPsc在以下方面的作用的信息， 疾病的过程中，相对较少的是了解正常的，生理 PrPc的功能。除了其内在的生物学意义外， PrPc的功能可能在理解疾病的发病机制中很重要。 朊病毒病，因为它已被建议，这一功能的损害，作为一个 转化为PrPsc的结果可以解释疾病的一些特征 表型 最近出现的几条证据表明，PrPc可能会发挥作用， 在必需微量金属的细胞代谢中起重要作用， 铜最令人信服的结果是，铜与低微摩尔 来自PrP缺失小鼠脑的膜组分显示出对PrPc的亲和力， 5%的正常含量的离子铜，和神经元铜锌 来自这些小鼠的超氧化物歧化酶的酶活性较低， 比正常小鼠的酶含有更少的放射性铜。在 此外，我自己的实验室最近表明，铜离子迅速， 显著改变PrPc在培养的神经元中的细胞运输。采取 总之，这些发现构成了正常的最实质性的线索， PrPc的功能在发现该蛋白质后的15年内出现。 他们提出了PrPc可能在细胞通路中起作用的假设 负责铜离子的摄取、递送或排泄。结果还 增加了在朊病毒感染期间铜代谢可能改变的可能性。 疾病，并认为铜水平的操纵可能是有用的治疗 紊乱 在本应用程序中，我们将通过（1）分析 在细胞和生化水平上PrPc和铜之间的相互作用， 哺乳动物细胞;（2）利用酵母S.酿酒酵母阐明的作用， PrPc在铜贩运中的作用，（3）通过表征铜 和疾病特异性同种型PrPsc，以及（4）通过使用PET对 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.