Quality control mechanisms against misfolded rhodopsins in Drosophila.

针对果蝇中错误折叠视紫红质的质量控制机制。

• 批准号: 8301711
• 负责人: HYUNG D RYOO
• 金额: $ 33.8万
• 依托单位: NEW YORK UNIVERSITY SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-01 至 2014-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8301711
• 关键词: Affect; Age-Years; Alleles; Amino Acid Substitution; Animal Model; Attention; Binding; Biological; Biological Assay; Blindness; Cells; Cytoplasm; Development; Disease; Drosophila genus; Employee Strikes; Endoplasmic Reticulum; Endoplasmic Reticulum Degradation Pathway; Gene Dosage; Gene Expression; Genes; Genetic; Genetic Transcription; Goals; Hereditary Disease; Homologous Gene; Human; Inborn Genetic Diseases; Individual; Longevity; Mammalian Cell; Mediating; Messenger RNA; Modeling; Mutation; Outcome Study; Pathway interactions; Phosphoric Monoester Hydrolases; Phosphorylation; Process; Property; Protein Dephosphorylation; Proteins; Quality Control; RNA Binding; RNA Interference; RNA Recognition Motif; RNA Splicing; Regulation; Retina; Retinal; Retinal Degeneration; Retinitis Pigmentosa; Rhodopsin; Role; Signal Pathway; Signal Transduction; Stress; Testing; Therapeutic; Ubiquitin; Yeasts; abstracting; age related; endonuclease; endoplasmic reticulum stress; fly; genome-wide; high throughput analysis; insight; interest; multicatalytic endopeptidase complex; mutant; novel; novel therapeutics; overexpression; phosphatase inhibitor; protective effect; protein complex; protein folding; protein misfolding; response; tool; transcription factor

Project Summary/Abstract Retinitis Pigmentosa is a group of inherited disorders that show a progressive loss of retinal function. One of the most common causes of Autosomal Dominant Retinitis Pigmentosa (ADRP) are mutations in the rhodopsin gene that disrupt its encoded protein's folding property. Our long-term goal is to understand how cells respond to stress caused by such rhodopsin proteins once they are synthesized in the endoplasmic reticulum (ER). As most cells have robust quality control mechanisms that can help eliminate such misfolded proteins from the ER, a better understanding of these mechanisms may have therapeutic implications. We focus on two specific ER quality control mechanisms that can help suppress retinal degeneration caused by misfolded rhodopsins. First is ER-Associated Degradation (ERAD), which refers to the ubiquitin-mediated degradation of misfolded proteins from the ER. Stimulation of ERAD can suppress retinal degeneration in a Drosophila model for ADRP, but the underlying mechanism remains poorly understood. In addition, ADRP may be suppressed by an intracellular signaling pathway activated by ER-stress, known as the Unfolded Protein Response (UPR). A central branch of the UPR is mediated by the unconventional splicing of xbp1 mRNA in the cytoplasm, leading to the synthesis of an active xbp1 transcription factor. Among the transcription targets of xbp1 include regulators of ERAD. To investigate mechanisms by which ERAD and the UPR suppress retinal degeneration in animal models of ADRP, we plan to use a combination of classical Drosophila genetics, cell biological analysis and high throughput RNAi assays. Specifically, we plan to investigate the precise mechanism by which misfolded rhodopsins are detected by the ERAD machinery and imported into the cytoplasm for degradation. In addition, we plan to study how the xbp1-mediated UPR pathway is regulated. We will test a specific hypothesis where xbp1 mRNA splicing is modulated by a specific phosphatase, and this phosphatase is in turn regulated by a regulatory subunit that binds to xbp1 mRNA. Any new genes or mechanisms identified through this approach will be examined for possible effects on retinal degeneration in a Drosophila model for ADRP, where an endogenous mutation in a rhodopsin encoding gene triggers a dominant form of age-related retinal degeneration. As the fly model shows a striking degree of similarity with the human condition, we believe that a successful outcome of this study may directly influence the development of new strategies against ADRP in humans.

项目摘要/摘要 色素性视网膜炎是一组遗传性疾病，显示出视网膜功能的逐渐丧失。之一 常染色体显性视网膜炎色素（ADRP）的最常见原因是Rhodopsin中的突变 破坏其编码蛋白质的折叠特性的基因。我们的长期目标是了解细胞的响应方式 一旦将这种视紫红质蛋白在内质网（ER）中合成后，它们是由这种压力引起的。作为 大多数细胞具有强大的质量控制机制，可以帮助消除这种错误折叠的蛋白质 er，对这些机制的更好理解可能具有治疗意义。我们专注于两个特定的 ER质量控制机制可以帮助抑制由错误折叠的视紫红蛋白引起的视网膜变性。 首先是与ER相关的降解（ERAD），它指的是泛素介导的降解错误折叠的降解 来自ER的蛋白质。刺激ERAD可以抑制ADRP果蝇模型中的视网膜变性， 但是基本机制仍然很少理解。此外，ADRP可能会被 细胞内信号通路被ER应力激活，称为展开的蛋白质反应（UPR）。一个 UPR的中央分支是由XBP1 mRNA在细胞质中的非常规剪接介导的， 与活动XBP1转录因子的合成。在XBP1的转录目标中包括 Erad的监管机构。调查ERAD和UPR抑制视网膜变性的机制 ADRP的动物模型，我们计划使用经典果蝇遗传学的组合，细胞生物学分析 和高通量RNAi分析。具体而言，我们计划调查确切机制 埃拉德机械检测到错误折叠的视紫红素，并进口到细胞质中以降解。在 此外，我们计划研究如何调节XBP1介导的UPR途径。我们将检验一个特定的假设 其中XBP1 mRNA剪接由特定的磷酸酶调节，而该磷酸酶也受到调节 通过与XBP1 mRNA结合的调节亚基。通过此确定的任何新基因或机制 将检查方法是否可能影响果蝇模型的ADRP视网膜变性，其中 编码基因的视紫红质中的内源性突变触发了与年龄相关的视网膜的主要形式 退化。由于苍蝇模型显示出与人类状况的相似程度，我们认为 这项研究的成功结果可能直接影响针对ADRP的新策略的制定 人类。