Signaling Cross-talk Between Endoplasmic Reticulum And Oxidative Stresses

内质网和氧化应激之间的信号串扰

• 批准号: RGPIN-2017-06414
• 负责人: Willmore, William
• 金额: $ 4.95万
• 依托单位: Carleton University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=744290
• 关键词: Signaling; Cross; talk; Between; Endoplasmic

Organisms must respond to a broad array of stresses which they may encounter during their lifespan. Stresses often occur, not as a single occurrence, but as multiple stresses which impinge upon the organism simultaneously. Stresses such as toxin stress, oxidative stress, low oxygen (hypoxic) stress and endoplasmic reticulum (ER) stress often occur concurrently. “Crosstalk” between multiple stresses often involves common protein factors which respond to a variety of extra- and intra-cellular signals. My research program focuses on one such protein that responds to multiple signalling processes and examines how these signals interact, either synergistically or antagonistically, to affect its function. Nuclear factor erythroid 2 like 1 (NFE2L1 or Nrf1) is a "cap'n'collar" basic leucine zipper transcription factor that heterodimerizes with small Maf proteins and bind to a DNA element known as the Antioxidant Response Element/Electrophile Response Element, required to transactivate antioxidant enzyme, phase 1 and 2 detoxification enzyme and proteasome subunit gene expression. Nrf1 responds to oxidative stress and regulates pathways involved in lipid metabolism, amino acid metabolism, proteasomal degradation, the citric acid cycle, and the mitochondrial respiratory chain. An unanswered question is the possibility that Nrf1 may also respond to ER stress, but how this occurs and how environmental stresses (toxin stress, hypoxia, oxidative stress) work in tandem with ER stress to affect Nrf1 function remains to be investigated. We recently demonstrated that a) hypoxia affects the way that Nrf1 is proteolytically processed, b) various environmental toxins affect the translocation of Nrf1 to the nucleus and c) phosphorylation of key tyrosines on the protein affect its ubiquitination and anchoring to the ER. The aims outlined in this proposal set out to demonstrate that cross-talk occurs between multiple environmental stressors and ER stress on Nrf1 function in mammalian cells. Aim 1 will examine the factors responsible for the proteolytic processing of Nrf1 and how these are altered by environmental stresses. Aim 2 will focus on stress-dependent post-translational modifications of the Nrf1 protein that affect its glycosylation, proteolytic processing and release from the ER under different stress conditions. Aim 3 will investigate the cross-talk between environmental stresses with ER stress in activating Nrf1. My long-term goals are to illustrate the importance of Nrf1 in the response to a broad range of cellular stresses and how these stresses act to affect its a) post-translational modification, b) release from the ER and translocation to the nucleus, c) proteolytic processing as well as determining whether multiple extra- and intracellular signals act synergistically or antagonistically on Nrf1. Similar mechanisms may apply to a number of different stress-response proteins.

生物体必须对它们在其生命周期中可能遇到的各种压力做出反应，压力通常不是单一发生的，而是同时作用于生物体的多种压力，例如毒素压力、氧化压力、低氧压力。低氧）应激和内质网（ER）应激经常同时发生，多种应激之间的“串扰”通常涉及对各种细胞外和细胞内信号做出反应的常见蛋白质因子。该计划重点研究一种对多种信号传导过程做出反应的蛋白质，并检查这些信号如何协同或拮抗地相互作用，以影响其功能。核因子红细胞 2 样 1（NFE2L1 或 Nrf1）是一种“cap'n'collar”基础蛋白。亮氨酸拉链转录因子，与小 Maf 蛋白异二聚化，并与称为抗氧化反应元件/电反应元件的 DNA 元件结合，需要反式激活抗氧化酶、1 相和 2 相解毒酶以及蛋白酶体亚基 Nrf1 基因表达对氧化应激作出反应，并调节参与脂质代谢、氨基酸代谢、蛋白酶体降解、柠檬酸循环和线粒体呼吸链的途径。 Nrf1 也有可能对 ER 应激做出反应，但这种反应是如何发生的以及环境应激（毒素应激、缺氧、氧化应激）如何发生我们最近证明，a) 缺氧会影响 Nrf1 的蛋白水解加工方式，b) 各种环境毒素会影响 Nrf1 向细胞核的易位，c) 关键蛋白的磷酸化。蛋白质上的酪氨酸影响其泛素化和锚定到内质网。该提案中概述的目标旨在证明多种环境压力源之间会发生串扰。哺乳动物细胞中 Nrf1 功能的内质网应激 目标 1 将研究负责 Nrf1 蛋白水解加工的因素以及环境应激如何改变这些因素 目标 2 将重点关注影响 Nrf1 蛋白的应激依赖性翻译后修饰。不同应激条件下内质网的糖基化、蛋白水解加工和释放 目标 3 将研究环境应激与内质网应激在激活过程中的相互作用。 Nrf1。我的长期目标是说明 Nrf1 在响应广泛的细胞应激中的重要性以及这些应激如何影响其 a) 翻译后修饰，b) 从 ER 释放和易位到细胞核，c) 蛋白水解处理以及确定多个细胞外和细胞内信号对 Nrf1 是否协同或拮抗作用。类似的机制可能适用于许多不同的应激反应蛋白。