Prion Cycle Regulation In Vivo

体内朊病毒循环调节

• 批准号: 8206123
• 负责人: TRICIA R. SERIO
• 金额: $ 31.43万
• 依托单位: BROWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-02-01 至 2015-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8206123
• 关键词: Address; Adopted; Amyloid Fibrils; Appearance; Biology; Cells; Cellular biology; Characteristics; Collection; Complex; Data; Development; Disease; Elements; Environment; Epigenetic Process; Equilibrium; Event; Frequencies; Goals; In Vitro; Indium; Individual; Knowledge; Life; Link; Mammals; Mediating; Mining; Mission; Modeling; Molecular; Molecular Chaperones; Molecular Conformation; Neurodegenerative Disorders; Nucleic Acids; Pathway interactions; Phenotype; Physiological; Physiology; Prion Diseases; Prions; Process; Protein Dynamics; Protein Structure Initiative; Proteins; Quality Control; Regulation; Research; Saccharomyces cerevisiae; Series; System; Testing; Variant; Work; Yeasts; base; cell growth regulation; disease characteristic; flexibility; fungus; in vitro activity; in vivo; innovation; insight; loss of function mutation; man; nucleic acid metabolism; overexpression; physical state; polypeptide; prion biogenesis; prion hypothesis; protein folding; protein misfolding; sup35; trait; transmission process

DESCRIPTION (provided by applicant): The prion hypothesis provides an explanation for a collection of previously inexplicable phenomena, ranging from the appearance, progression and spread of mammalian neurodegenerative disease to the non-Mendelian inheritance of unique traits in fungi. According to this idea, prion-associated phenotypes arise when a protein, known as a prion, adopts an alternative physical state and persist when that form self-replicates. This self- replication is mediated by the assembly of alternatively folded prions into aggregates, which template the con- version of other forms of the protein to a like state. The ability of prions to harness their conformational flexibil- ity is a central event in establishing distinct phenotypes, but this process becomes a multistep endeavor within the context of a living cell. Protein quality control pathways, prion biogenesis, and cell biology modify prion folding in vivo to create transmissible changes in physiology. A molecular understanding of how these forces intersect is a gap in current knowledge, limiting our ability to correlate prion folding mechanisms in vitro and their physiological consequences in vivo. As transitions between prion-associated phenotypes necessarily in- volve changes in protein state, these forces must converge on events that regulate prion dynamics in vivo. The long-term goal of this research is to elucidate the cellular mechanisms that influence prion folding to pro- duce transmissible changes in physiology. The overall objective of this application is to determine the molecu- lar mechanisms through which the prion folding pathway, cellular quality control, and other aspects of cell biol- ogy combine to create prion-associated phenotypes. Our approach is to determine the pathways through which variations in Sup35 sequence, conformation, and expression levels alter prion propagation in vivo. The central hypothesis is that the physical characteristics and abundance of Sup35 temper the efficiency with which mo- lecular chaperones recognize and/or process the prion form, thereby allowing distinct phenotypes to arise and persist but also to occasionally interconvert. Guided by strong preliminary data using the experimentally trac- table Sup35/[PSI+] prion of S. cerevisiae, this hypothesis will be tested through three specific aims: 1) Deter- mine the molecular mechanism by which sequence variants of Sup35 alter [PSI+] propagation, 2) Determine the molecular mechanism by which excess Hsp104 leads to [PSI+] loss, and 3) Determine the molecular mechanism by which Sup35 aggregation creates the [PSI+] phenotype. These proposed studies are innovative because they use a unique combination of experimental and mathematical analyses to test a new and dynamic model for prion-associated phenotypes. The proposed research is significant because it addresses the cellular regulation of prion folding, a poorly understood but significant factor that allows the prion hypothesis to create protein-based epigenetic elements in yeast. This knowledge, gained in the experimentally tractable yeast sys- tem, has the potential to provide new hypotheses that can be tested in more complex systems where a prion mechanism has been implicated. PUBLIC HEALTH RELEVANCE: The proposed research is relevant to public heath because the misfolding of prion proteins is associated with a wide array of familial, sporadic and transmissible neurodegenerative disease in man. Our current understanding of how protein misfolding correlates with disease characteristics is limited; thus, our proposed studies are relevant to NIH's mission because the knowledge gained here has the potential to provide a new framework for understanding disease dynamics in man.

描述（由申请人提供）：朊病毒假说为一系列以前无法解释的现象提供了解释，从哺乳动物神经退行性疾病的出现、进展和传播到真菌独特性状的非孟德尔遗传。根据这个想法，当一种被称为朊病毒的蛋白质采用另一种物理状态并在形成自我复制时持续存在时，就会出现与朊病毒相关的表型。这种自我复制是通过交替折叠的朊病毒组装成聚集体来介导的，该聚集体以其他形式的蛋白质向类似状态的转变为模板。朊病毒利用其构象灵活性的能力是建立不同表型的核心事件，但这个过程在活细胞的背景下变成了一个多步骤的努力。蛋白质质量控​​制途径、朊病毒生物发生和细胞生物学改变体内朊病毒折叠，从而产生可传播的生理变化。对这些力如何交叉的分子理解是当前知识的一个空白，限制了我们将体外朊病毒折叠机制与其体内生理后果关联起来的能力。由于朊病毒相关表型之间的转变必然涉及蛋白质状态的变化，因此这些力量必须集中在调节体内朊病毒动力学的事件上。这项研究的长期目标是阐明影响朊病毒折叠以产生可传播的生理变化的细胞机制。本申请的总体目标是确定朊病毒折叠途径、细胞质量控制和细胞生物学其他方面结合起来创建朊病毒相关表型的分子机制。我们的方法是确定 Sup35 序列、构象和表达水平的变化改变朊病毒体内传播的途径。核心假设是，Sup35 的物理特征和丰度调节了分子伴侣识别和/或处理朊病毒形式的效率，从而允许不同的表型出现和持续，但也偶尔相互转化。在使用酿酒酵母实验可追踪的 Sup35/[PSI+] 朊病毒的强有力的初步数据的指导下，这一假设将通过三个具体目标进行检验： 1) 确定 Sup35 序列变体改变 [PSI+] 的分子机制传播，2) 确定过量 Hsp104 导致 [PSI+] 丢失的分子机制，以及 3) 确定 Sup35 聚集产生[PSI+]表型。这些拟议的研究具有创新性，因为它们使用实验和数学分析的独特组合来测试朊病毒相关表型的新动态模型。这项拟议的研究意义重大，因为它解决了朊病毒折叠的细胞调控问题，这是一个鲜为人知但重要的因素，它允许朊病毒假说在酵母中创建基于蛋白质的表观遗传元件。这些知识是在实验上易于处理的酵母系统中获得的，有可能提供新的假设，可以在涉及朊病毒机制的更复杂的系统中进行测试。 公共健康相关性：拟议的研究与公共健康相关，因为朊病毒蛋白的错误折叠与人类多种家族性、散发性和传染性神经退行性疾病有关。我们目前对蛋白质错误折叠如何与疾病特征相关的理解是有限的。因此，我们提出的研究与 NIH 的使命相关，因为在这里获得的知识有可能为理解人类疾病动态提供新的框架。