Biological functions of melanoma antigen (MAGE) proteins

黑色素瘤抗原 (MAGE) 蛋白的生物学功能

• 批准号: RGPIN-2020-04961
• 负责人: Wevrick, Rachel
• 金额: $ 2.33万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=740313
• 关键词: Biological; functions; melanoma; antigen; MAGE

The abundance and subcellular localization of proteins contributes to the ctivities that take place inside cells. Both protein stability and localization are determined in part by post-translational modification. The proposed research specifically considers the role of the reversible attachment of a 76 residue ubiquitin protein to substrate proteins, which dynamically changes the stability, activity, or subcellular localization of the ubiquitinated protein. For example, cell cycle proteins undergo highly regulated ubiquitination and deubiquitination, fine tuning their stability, activity and localization. However, the proteins that perform the reversible ubiquitination / deubiquitination processes, and other proteins that modify the activity of these ubiquitin ligases and deubiquitinases are poorly understood. Our previous research has demonstrated that Melanoma Antigen Gene (MAGE) proteins regulate the ubiquitination and deubiquitination of proteins important for a variety of physiological processes. In particular, the L2 member of the MAGE family of proteins (MAGEL2) regulates the intracellular localization and stability of other proteins. Our team found that MAGEL2 forms a functional complex with E3 ubiquitin ligases (e.g. RBX1-SCF) and deubiquitinases (e.g. USP7), thereby regulating circadian rhythm processes through effects on the activity and stability of master clock components. We found that MAGEL2 regulates the stability of BBS proteins important for the function of centrosomes and of cilia, subcellular organelles that sense and respond to signals in the extracellular environment. We found that MAGEL2 and another MAGE protein, namely necdin, regulate the intracellular shuttling of the leptin receptor through processes dependent on ESCRT (endosomal sorting complexes required for transport) machinery. Our research program objective is to explore the mechanisms for regulation of intracellular shuttling and stability of proteins by protein ubiquitination. The importance of MAGE proteins in this process is evident from the observations that mutation in the genes encoding MAGE proteins cause disease in humans (MAGEL2 in Schaaf-Yang syndrome, MAGED2 in antenatal Bartter syndrome, MAGEG1 in a chromosome breakage syndrome), with phenotypes in mouse MAGE gene knockouts as well. We will use molecular and cellular models to determine the role of MAGE proteins, which are components of ubiquitination (Ub) complexes. Specifically, we will use protein-protein interaction techniques to identify components of the MAGE-ubiquitin ligase-deubiquitinase complexes; determine how MAGE proteins fine tune cellular processes using cell lines in culture and 3) examine how genes and proteins important in cellular processes are regulated by ubiquitination in tissues. Ultimately, this research will explore how modification of proteins by ubiquitination and deubiquitination fine tunes the activity of proteins in the cell.

蛋白质的丰度和亚细胞定位有助于细胞内发生的活动。蛋白质稳定性和定位部分由翻译后修饰决定。拟议的研究特别考虑了 76 个残基泛素蛋白与底物蛋白可逆连接的作用，这动态地改变了泛素化蛋白的稳定性、活性或亚细胞定位。例如，细胞周期蛋白经历高度调控的泛素化和去泛素化，微调其稳定性、活性和定位。然而，人们对执行可逆泛素化/去泛素化过程的蛋白质以及修饰这些泛素连接酶和去泛素酶活性的其他蛋白质知之甚少。我们之前的研究表明，黑色素瘤抗原基因 (MAGE) 蛋白可调节对多种生理过程很重要的蛋白质的泛素化和去泛素化。特别是，MAGE 蛋白家族的 L2 成员 (MAGEL2) 调节其他蛋白的细胞内定位和稳定性。我们的团队发现MAGEL2与E3泛素连接酶（例如RBX1-SCF）和去泛素酶（例如USP7）形成功能复合物，从而通过影响主时钟组件的活性和稳定性来调节昼夜节律过程。我们发现 MAGEL2 调节 BBS 蛋白的稳定性，这些蛋白对于中心体和纤毛（感知和响应细胞外环境中的信号的亚细胞器）的功能很重要。我们发现 MAGEL2 和另一种 MAGE 蛋白（即 necdin）通过依赖于 ESCRT（运输所需的内体分选复合物）机制的过程调节瘦素受体的细胞内穿梭。我们的研究计划目标是探索通过蛋白质泛素化调节细胞内穿梭和蛋白质稳定性的机制。 MAGE 蛋白在此过程中的重要性从观察到编码 MAGE 蛋白的基因突变导致人类疾病（Schaaf-Yang 综合征中的 MAGEL2、产前 Bartter 综合征中的 MAGED2、染色体断裂综合征中的 MAGEG1）的观察中可见一斑，其表型小鼠 MAGE 基因敲除也是如此。我们将使用分子和细胞模型来确定 MAGE 蛋白的作用，MAGE 蛋白是泛素化 (Ub) 复合物的组成部分。具体来说，我们将使用蛋白质-蛋白质相互作用技术来鉴定 MAGE-泛素连接酶-去泛素酶复合物的成分；确定 MAGE 蛋白如何使用培养的细胞系微调细胞过程，3) 检查组织中的泛素化如何调节细胞过程中重要的基因和蛋白质。最终，这项研究将探索通过泛素化和去泛素化修饰蛋白质如何微调细胞中蛋白质的活性。