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.

项目总结/摘要 视网膜色素变性是一组遗传性疾病，表现为视网膜功能的进行性丧失。之一 常染色体显性视网膜色素变性（ADRP）的最常见原因是视紫红质突变 破坏其编码蛋白质折叠特性的基因。我们的长期目标是了解细胞如何反应 一旦这些视紫红质蛋白在内质网（ER）中合成，它们就引起应激。作为 大多数细胞都具有强大的质量控制机制，可以帮助从细胞中消除这种错误折叠的蛋白质。 ER，更好地理解这些机制可能具有治疗意义。我们专注于两个具体的 ER质量控制机制可以帮助抑制由错误折叠的视紫红质引起的视网膜变性。 首先是ER相关降解（ERAD），它是指泛素介导的错误折叠的 ER的蛋白质。刺激ERAD可以抑制果蝇ADRP模型中的视网膜变性， 但其潜在机制仍知之甚少。此外，ADRP可能被抑制， ER应激激活的细胞内信号通路，称为未折叠蛋白反应（UPR）。一 UPR的中央分支由细胞质中xbp 1 mRNA的非常规剪接介导， 涉及活性XBP 1转录因子的合成。xbp 1的转录靶点包括 ERAD的监管机构。为了研究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，细胞生物学分析相结合 和高通量RNAi测定。具体地说，我们计划研究精确的机制， 错误折叠的视紫红质被ERAD机器检测到，并被输入细胞质进行降解。在 此外，我们计划研究xbp 1介导的UPR通路是如何调节的。我们将测试一个特定的假设 其中xbp 1 mRNA剪接受一种特异性磷酸酶调节，而这种磷酸酶反过来又受 通过一个与xbp 1 mRNA结合的调节亚基。任何新的基因或机制，通过这一发现 将在ADRP的果蝇模型中检查方法对视网膜变性的可能影响，其中 视紫红质编码基因的内源性突变引发了一种与年龄相关的显性视网膜病变， 退化由于苍蝇模型显示出与人类状况惊人的相似程度，我们相信， 这项研究的成功结果可能直接影响ADRP新策略的发展， 人类