TSE Prion Cell Biology

传染性海绵状脑病（Transmissible spongiform encephalopathies，TSE）是一组影响多种哺乳动物的神经退行性疾病，包括绵羊和山羊（羊瘙痒病）、鹿属（cervid spp.）（慢性消耗性疾病）和人类（克雅氏病）。 我们的研究集中在朊病毒蛋白（PrP），因为这种蛋白在控制TSE发病机制的许多方面，如疾病易感性和种间传播中起着关键作用。 TSE疾病的中心事件涉及正常宿主细胞朊病毒蛋白（PrPC）转化为部分蛋白酶抗性、聚集的疾病相关同种型（PrPSc）。 TSE引起的病理学改变通常与PrP-res沉积有关，但神经退行性变的机制尚不清楚。 感染因子的性质，称为朊病毒，仍然不确定，但被认为主要由错误折叠的PrP组成，可能与另一种宿主辅助分子复合。 PrPC是糖基磷脂酰肌醇（GPI）锚定的糖蛋白，并且体内产生的大多数PrPSc含有该GPI锚。 膜协会的正常和疾病相关的PrP亚型可能会影响朊病毒疾病和PrPC功能的许多特点。 我们的工作重点是阐明摄取，复制和传播的朊病毒的机制，除了确定哺乳动物朊病毒的生化组成。 在2011年，我们：1）继续我们的工作与一个新的化合物，应该允许可视化的TC标记的蛋白质的电子显微镜; 2）显示纯化的PrP可以转化为TSE代理，提供深入了解朊病毒的生化组成; 3）创建新的菌株的TSE代理使用重组PrP; 4）开发了新的纯化方法，以产生具有和不具有翻译后修饰的高度纯化的PrPSc;和5）获得了PrPSc结构的数据，表明转化为这种同种型涉及PrPC的完全重折叠，翻译修饰对PrPSc的核心结构的影响最小。

Transmissible spongiform encephalopathies (TSEs) are a group of neurodegenerative diseases affecting a wide variety of mammals including sheep and goats (scrapie), cervid spp. (chronic wasting disease), and humans (Creutzfeldt-Jakob disease). Our studies are focused on the prion protein (PrP) due to the critical role of this protein in controlling many aspects of TSE pathogenesis such as susceptibility to disease and interspecies transmission. A central event in TSE disease involves the conversion of the normal host cellular prion protein (PrPC) to a partially protease-resistant, aggregated, disease-associated isoform (PrPSc). TSE-induced pathology is usually associated with PrP-res deposition, but the mechanism of neurodegeneration is not understood. The nature of the infectious agent, called a prion, remains uncertain but is thought to be composed primarily of misfolded PrP, perhaps in complex with another host accessory molecule(s). PrPC is a glycosylphosphatidylinositol (GPI)-anchored glycoprotein, and the majority of PrPSc produced in vivo contains this GPI anchor. Membrane association of both normal and disease-associated PrP isoforms may influence many features of prion disease and PrPC function. Our work is focused on elucidating mechanisms of uptake, replication, and spread of prions, in addition to determining the biochemical composition of mammalian prions. In 2011, we have: 1) continued our work with a new compound that should allow visualization of TC-tagged proteins by electron microscopy; 2) shown that purified PrP can be converted into a TSE agent, providing insight into the biochemical composition of prions; 3) created novel strains of TSE agents using recombinant PrP; 4) developed new purification methods to produce highly purified PrPSc with and without post-translational modifications; and 5) obtained data on the structure of PrPSc to show that conversion to this isoform involves complete refolding of PrPC and that post-translational modifications have a minimal impact on the core structure of PrPSc.