STRUCTURAL STUDIES ON TRANSMEMBRANE PRION PROTEIN

跨膜朊病毒蛋白的结构研究

• 批准号: 6742811
• 负责人: VISHWANATH R LINGAPPA
• 金额: $ 21万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6742811
• 关键词: conformation; density gradient ultracentrifugation; electron microscopy; laboratory mouse; membrane proteins; molecular cloning; prions; protein biosynthesis; protein isoforms; protein protein interaction; protein purification; protein sequence; protein signal sequence; protein structure function; regulatory gene; scrapie; tissue /cell culture

A distinctive feature of prion protein (PrP) biogenesis, which appears central to an understanding of prion disease pathophysiology, is the observation that nascent PrP is synthesized in the form of at least three distinctive conformers that also differ in transmembrane topology. A growing body of evidence suggests that one of these, termed (Ctm)PrP, triggers a final common pathway of apoptosis occurring in response to both genetic and infectious prion disease, while another conformer, termed (Sec)PrP, is anti-apoptotic and neuroprotective. Work over the last decade has revealed a number of means by which the mix of conformers synthesized from an initially homogeneous population of nascent PrP chains can be altered. In particular, the signal sequence, and a charged region termed the Stop Transfer Effector (STE) sequence immediately preceding the transmembrane region, have been demonstrated to be sequence determinants of PrP topology. More recent data suggests that: i) other regions besides the signal sequence and STE sequence may contribute to regulation of PrP transmembrane topology and conformation, ii) interaction of distinct domains within PrP are involved in the protein's topogenesis, and iii) mapping of protein-protein interactions during translocation may provide useful information for conformer manipulation. Here we propose studies designed to i) explore new topogenic sequences and their interactions in cis, and ii) identify the partner proteins with which nascent PrP is involved in trans. We will then use this information to better understand the mechanism by which individual PrP conformers are generated, and the relationship of those mechanisms to signaling in infectious scrapie. In the long run, this work may also make possible the development of novel approaches to treatment of prion disease through conformer manipulation.

朊病毒蛋白 (PrP) 生物发生的一个显着特征是理解朊病毒疾病病理生理学的核心，即观察到新生的 PrP 以至少三种独特的构象异构体的形式合成，这些构象异构体的跨膜拓扑结构也不同。越来越多的证据表明，其中一种称为 (Ctm)PrP 的构象异构体，可触发响应遗传性和传染性朊病毒疾病而发生的细胞凋亡的最终共同途径，而另一种构象异构体，称为 (Sec)PrP，具有抗凋亡和神经保护作用。过去十年的工作揭示了多种方法，通过这些方法，构象异构体的混合 由最初同质的新生 PrP 链群合成的序列可以被改变。特别是，信号序列和紧邻跨膜区之前的称为停止转移效应器 (STE) 序列的带电区域已被证明是 PrP 拓扑结构的序列决定因素。最近的数据表明：i) 除了信号序列和 STE 序列之外的其他区域可能有助于 PrP 跨膜拓扑和构象的调节，ii) PrP 内不同结构域的相互作用参与蛋白质的拓扑发生，以及 iii) 易位过程中蛋白质-蛋白质相互作用的图谱可能为构象异构体操作提供有用的信息。在这里，我们提出的研究旨在 i) 探索新的拓扑序列及其顺式相互作用，以及 ii) 识别合作伙伴 新生 PrP 参与反式的蛋白质。然后，我们将利用这些信息来更好地了解单个 PrP 构象异构体的生成机制，以及这些机制与传染性痒病中信号传导的关系。从长远来看，这项工作还可能使通过构象异构体操纵开发治疗朊病毒病的新方法成为可能。