Regulation of Amyloid Fibril Assembly by Hsp40 Molecular Chaperones

Hsp40 分子伴侣对淀粉样原纤维组装的调节

• 批准号: 7753308
• 负责人: Daniel W Summers
• 金额: $ 2.76万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7753308
• 关键词: Address; Alzheimer' s Disease; Amyloid; Amyloid Fibrils; Amyloid deposition; Automobile Driving; Benign; Binding; Biochemical; Biological Models; Buffers; C-terminal; Cells; Complex; Data; Disease; Glutamine; Homologous Gene; Human; Huntington Disease; Kinetics; Length; Light; Modeling; Molecular Chaperones; Molecular Conformation; Mutate; N-terminal; Nature; Neurodegenerative Disorders; Neurons; Outcome; Pathway interactions; Prions; Process; Proteins; Regulation; Research; Saccharomycetales; Senile Plaques; Structure; Study models; Testing; Therapeutic; Toxic effect; Work; Yeasts; amyloid formation; conformer; cytotoxic; human Huntingtin protein; human disease; insight; killings; neuron loss; non-prion; overexpression; prevent; protein aggregate; protein aggregation; protein misfolding; public health relevance; therapeutic target; yeast prion; yeast protein

DESCRIPTION (provided by applicant): Protein aggregation and amyloid deposition characterize a variety of neurodegenerative disorders including Alzheimer's Disease and Huntingtin's disease. The conversion of a native protein into mature amyloid fibril is a complex, poorly understood process. The regulation of amyloid assembly within the cell has significant relevance to several neurodegenerative disorders and further understanding of the mechanisms behind this process will provide substantial therapeutic insight. Budding yeast possess several endogenous proteins called prions that assemble into intracellular, amyloid-like fibrils. The prion [RNQ+] is toxic to yeast when the protein Rnq1 is overexpressed. Thus, the yeast prion [RNQ+] serves as a tractable, yet powerful model system to study fibril assembly and how molecular chaperones regulate this pathway to prevent the accumulation of cytotoxic species. Specifically, we find that the Type 1 Hsp40 Ydj1 interacts with the Gln/Asn rich prion domain from Rnq1 and modulates the aggregation and toxicity of this fragment. Two specific questions will be addressed: 1) What features in the yeast prion [RNQ+] regulate assembly into toxic or benign aggregates? 2) How does the Hsp40 Ydj1 maintain the Rnq1 prion domain in a benign conformation? Specific Aim 1 will investigate how full-length Rnq1 and the Gln/Asn-rich prion domain assemble into biochemically-distinct protein aggregates. We predict the efficiency of prion assembly will determine whether toxic, intermediate species accumulate when these proteins are expressed. Specific Aim 2 will address how Ydj1 interacts with the Rnq1 prion domain and buffers the accumulation of SDS-insoluble prion. Ydj1 possesses several features distinct from other Hsp40s yet shared with its human homolog Hdj-2 that may contribute to specific recognition of hydrophilic, aggregate-prone substrates. Altogether, these studies will yield additional mechanistic understanding of how molecular chaperones modulate amyloid assembly to prevent, the aberrant accumulation of toxic protein aggregates. PUBLIC HEALTH RELEVANCE: Numerous neurodegenerative disorders are caused by the accumulation of misfolded proteins within the cell. This research will examine how cells regulate the assembly of protein aggregates into toxic or benign forms.

描述（由申请人提供）：蛋白质聚集和淀粉样蛋白沉积是多种神经退行性疾病的特征，包括阿尔茨海默病和亨廷顿舞蹈病。天然蛋白向成熟淀粉样蛋白纤维的转化是一个复杂的、鲜为人知的过程。细胞内淀粉样蛋白组装的调节与几种神经退行性疾病具有重要的相关性，进一步了解这一过程背后的机制将提供实质性的治疗见解。出芽酵母具有几种称为朊病毒的内源性蛋白质，这些朊病毒组装成细胞内淀粉样原纤维。当蛋白Rnq1过表达时，朊病毒[RNQ+]对酵母是有毒的。因此，酵母朊病毒[RNQ+]作为一个易于处理的，但强大的模型系统来研究原纤维组装和分子伴侣如何调节这一途径，以防止细胞毒性物质的积累。具体来说，我们发现1型Hsp40 Ydj1与Rnq1的富含Gln/Asn的朊病毒结构域相互作用，并调节该片段的聚集和毒性。将解决两个具体问题：1)酵母朊病毒[RNQ+]中的哪些特征调节组装成有毒或良性聚集体？2) Hsp40 Ydj1如何维持Rnq1朊病毒结构域处于良性构象？特异性目标1将研究全长Rnq1和富含Gln/ asn的朊病毒结构域如何组装成生物化学上不同的蛋白质聚集体。我们预测朊病毒组装的效率将决定是否有毒，中间物种积累时，这些蛋白质的表达。特异性目标2将讨论Ydj1如何与Rnq1朊病毒结构域相互作用并缓冲sds不溶性朊病毒的积累。Ydj1具有与其他hsp40不同的几个特征，但与人类同源物Hdj-2相同，这些特征可能有助于特异性识别亲水、易聚集的底物。总之，这些研究将对分子伴侣如何调节淀粉样蛋白组装以防止有毒蛋白质聚集体的异常积累产生额外的机制理解。公共卫生相关性：许多神经退行性疾病是由细胞内错误折叠蛋白质的积累引起的。这项研究将检查细胞如何调节蛋白质聚集体的组装成有毒或良性形式。