STRUCTURAL STUDIES ON TRANSMEMBRANE PRION PROTEIN

跨膜朊病毒蛋白的结构研究

• 批准号: 7173814
• 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
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7173814
• 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）生物发生的一个显著特征是观察到新生PrP以至少三种不同的构象异构体的形式合成，这些构象异构体在跨膜拓扑结构上也不同，这对于理解朊病毒疾病的病理生理学至关重要。越来越多的证据表明，其中之一，称为（Ctm）PrP，触发细胞凋亡的最终共同途径发生在遗传和传染性朊病毒疾病，而另一个构象，称为（Sec）PrP，是抗凋亡和神经保护。过去十年的工作已经揭示了一些方法，通过这些方法，构象异构体的混合物可以被改变。 由最初同质的新生PrP链群体合成的PrP链可以改变。特别是，信号序列，和一个带电的区域称为停止转移效应（STE）序列之前的跨膜区域，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调节PrP跨膜拓扑结构和构象，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）易位期间蛋白质-蛋白质相互作用的映射可能为构象操纵提供有用的信息。在这里，我们提出的研究设计，i）探索新的拓扑序列和它们的相互作用的顺式，和ii）确定合作伙伴 蛋白质与新生PrP参与trans.我们将使用这些信息，以更好地了解个别PrP构象生成的机制，以及这些机制的关系，在传染性瘙痒症的信号。从长远来看，这项工作也可能使开发新的方法来治疗朊病毒疾病通过构象操纵。