Defining the cellular role of TMCO1, a glaucoma-linked gene of unknown function

定义 TMCO1（一种功能未知的青光眼相关基因）的细胞作用

• 批准号: 9249051
• 负责人: Robert J Keenan
• 金额: $ 19.19万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-04-01 至 2018-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9249051
• 关键词: Affect; Alpha Cell; American; Anabolism; Apoptosis; Apoptosis Regulation Gene; Apoptotic; Bacterial Proteins; Biochemical; Biochemistry; Biogenesis; Biological Assay; Blindness; Cell Extracts; Cell Survival; Cells; Cellular Membrane; Cessation of life; Data; Defect; Dependence; Development; Disease; Distant; Endoplasmic Reticulum; Eye; Future; Genes; Glaucoma; Goals; Human; In Vitro; Induction of Apoptosis; Integral Membrane Protein; Knock-out; Lead; Link; Mass Spectrum Analysis; Membrane; Membrane Proteins; Microscopy; Microsomes; Modeling; Molecular; Monitor; Neurodegenerative Disorders; Optic Nerve; Pathogenesis; Pathway interactions; Patients; Phylogenetic Analysis; Population; Positioning Attribute; Prevalence; Primary Open Angle Glaucoma; Protein Biosynthesis; Proteins; Proteome; Proteomics; Retinal Ganglion Cells; Ribosomes; Role; Single Nucleotide Polymorphism; System; Tissues; Work; base; disease phenotype; experimental study; genome wide association study; high risk; human disease; in vivo; insight; member; novel; novel therapeutic intervention; public health relevance

 DESCRIPTION (provided by applicant): The goal of this project is to define the cellular role of TMCO1, a glaucoma-linked gene which encodes an integral membrane protein of unknown function. More than two million Americans are affected by glaucoma, a group of neurodegenerative diseases involving optic nerve damage resulting from the apoptotic death of retinal ganglion cells (RGC). Despite its prevalence, little is known about the development and progression of glaucoma on the molecular level. Multiple genome-wide association studies in different populations have recently identified associations between primary open angle glaucoma (POAG)-the most common form of glaucoma-and single nucleotide polymorphisms (SNPs) around a gene called TMCO1. Intriguingly, some of these SNPs are correlated with changes in expression levels of the TMCO1 gene. That such changes contribute to the pathogenesis of glaucoma is consistent with previous studies suggesting that TMCO1 is an apoptosis regulator expressed in multiple eye tissues, including RGCs. However, the role of TMCO1 in glaucoma remains unknown, because its cellular and molecular functions are completely undefined. We recently uncovered a possible function for TMCO1 as a result of a phylogenetic analysis. We found that TMCO1 belongs to a previously unrecognized superfamily of distantly related proteins that are broadly involved in membrane protein biogenesis. Furthermore, we have obtained functional data showing that TMCO1 localizes to the endoplasmic reticulum (ER) membrane where it interacts with ribosomes and other components of the known biosynthetic machinery. Based on these preliminary data, we hypothesize that TMCO1 functions to insert certain membrane proteins into the ER during their biosynthesis. An attractive model is that defects in TMCO1-dependent insertion lead to misfolding, accumulation of toxic aggregates and induction of apoptosis, hallmarks of many neurodegenerative diseases. Alternatively, the disease phenotype might be linked to failed biogenesis of a specific protein(s) that is essential for normal RGC survival. We are uniquely positioned to define the cellular role of TMCO1 using quantitative proteomics, cell-based localization studies and in vitro biochemistry. In Aim 1 we will identify human membrane proteins whose biogenesis is dependent on TMCO1. In Aim 2 we will develop an in vitro insertion assay and demonstrate that TMCO1 is a bona fide insertase. This is a high-risk project that promises high-impact payoff. By defining the function of TMCO1 and identifying substrates on which it acts, these studies will provide a molecular framework to understand how changes in TMCO1 expression are linked to the development of glaucoma. More broadly, if our hypothesis is correct, we will have discovered a new membrane protein insertion system in the endoplasmic reticulum. Such work would impact our understanding of membrane protein biogenesis and its role in human disease.

 描述（由适用提供）：该项目的目的是定义TMCO1的细胞作用，TMCO1是一种青光眼连接的基因，它编码了功能未知的整体膜蛋白。超过200万美国人受到青光眼的影响，青光眼是一组神经退行性疾病，涉及视网膜神经节细胞凋亡死亡（RGC）导致视神经损伤。尽管盛行，但对分子水平的青光眼的发展和发展知之甚少。在不同人群中进行的多个基因组关联研究最近确定了原发性敞开角度青光眼（POAG）之间的相关性 - 围绕TMCO1的基因围绕基因的青光眼和单一核丁基多态性（SNP）的最常见形式。有趣的是，其中一些SNP与TMCO1基因表达水平的变化相关。这种变化有助于青光眼的发病机理与以前的研究一致，表明TMCO1是在包括RGC在内的多个眼组织中表达的凋亡调节剂。然而，TMCO1在青光眼中的作用仍然未知，因为其细胞和分子功能是完全未确定的。由于系统发育分析，我们最近发现了TMCO1的可能功能。我们发现，TMCO1属于以前未被认可的超家族蛋白质，这些蛋白质广泛参与膜蛋白生物发生。此外，我们获得了功能数据，表明TMCO1定位于内质网（ER）膜，在其中它与已知生物合成机械的核糖体和其他成分相互作用。基于这些初步数据，我们假设TMCO1在其生物合成过程中将某些膜蛋白插入ER中。一个有吸引力的模型是，TMCO1依赖性插入的缺陷导致错误折叠，有毒骨料的积累和凋亡的诱导，许多神经退行性疾病的标志。 这对于正常的RGC存活至关重要。我们可以使用定量蛋白质组学，基于细胞的定位研究和体外生物化学来确定TMCO1的细胞作用。在AIM 1中，我们将确定其生物发生取决于TMCO1的人类膜蛋白。在AIM 2中，我们将开发一种体外插入测定法，并证明TMCO1是一种bona插入酶。这是一个高风险项目，承诺高影响力。通过定义TMCO1的功能并确定其作用的底物，这些研究将提供一个分子框架，以了解TMCO1表达的变化如何与青光眼的发展相关。更广泛地说，如果我们的假设正确，我们将在内质网中发现一种新的膜蛋白插入系统。这种工作将影响我们对膜蛋白生物发生及其在人类疾病中的作用的理解。