TSE Prion Cell Biology

传染性海绵状脑病(TSEs)是一组影响多种哺乳动物的神经退行性疾病，包括绵羊、山羊(瘙痒病)、鹿。(慢性消耗性疾病)和人类(克雅氏病)。我们的研究主要集中在Prion蛋白(PrP)上，因为该蛋白在控制TSE发病的许多方面起着关键作用，如疾病易感性和物种间传播。TSE病的一个中心事件涉及将正常宿主细胞内的Prion蛋白(PrPC)转换为部分抗蛋白酶的、聚集的、疾病相关的亚型(PrPSc)。TSE诱导的病理通常与PrP-res沉积有关，但其神经退行性变的机制尚不清楚。这种被称为PrP的感染性病原体的性质尚不清楚，但人们认为它主要由错误折叠的PrP组成，可能与另一种宿主辅助分子(S)形成了复合体。PrPC是一种糖基磷脂酰肌醇(GPI)锚定的糖蛋白，体内产生的PrPSc大多含有这个GPI锚定。正常PrP亚型和疾病相关PrP亚型的膜结合可能影响PrPC疾病的许多特征和PrPC功能。我们的工作集中在阐明Pron的摄取、复制和传播的机制，以及确定哺乳动物Pron的生化组成。 2010年，我们完成了以下工作：1)进一步鉴定了我们用于PrPC荧光标记的四半胱氨酸(TC)标记系统，显示了TC标记对蛋白质间相互作用和PrPC代谢的空间效应有限，表明TC标记可用作蛋白质之间相互作用位点的紧凑探针；2)继续我们的新化合物的工作，有望通过电子显微镜观察TC标记的蛋白质；3)证明重组小鼠PrP的错误折叠聚集体可在动物体内诱导TSE病；以及4)建立了原代细胞培养模型，用于研究Pron蛋白的运输。

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 2010, we have: 1) further characterized our tetracysteine (TC) tagging system for fluorescent labeling of PrPC by showing that TC tag insertion has limited steric effects on protein-protein interactions and PrPC metabolism, suggesting the TC tag can be used as a compact probe for sites of interaction between proteins; 2) continued our work with a new compound that should allow visualization of TC-tagged proteins by electron microscopy; 3) shown that TSE disease can be induced in animals inoculated with misfolded aggregates of recombinant mouse PrP; and 4) established primary cell culture models for studying the trafficking of prion proteins.