Deciphering the crosstalk between methionine metabolism and methyltransferases in health and disease

项目摘要/摘要 蛋氨酸代谢是蛋白质合成、线粒体功能、抗氧化剂的中枢调节因子 防御和其他关键的细胞过程。通过蛋氨酸代谢严密调控蛋氨酸通量 通路对于健康的细胞功能是必不可少的。不足为奇的是，这种基本代谢的失衡 这条通路被认为与多种疾病有关。然而，蛋氨酸变化之间的分子联系 下游细胞过程的可获得性和失调仍不清楚。蛋氨酸和三磷酸腺苷是 生产甲基供体S-腺苷蛋氨酸的唯一前体，本金和速率- 甲基转移酶(MTS)的限制性甲基供体，它通过 甲基转移到不同的底物上。尽管蛋氨酸代谢的重新编程已经 已在不同的病理条件下观察到，目前尚不清楚MTS下游与蛋氨酸的联系 代谢对这些病理条件的发展以及是什么介导了这种特异性 互动，代表着重大的知识差距。我假设特定的MTS的识别 将揭示蛋氨酸代谢调节基本细胞过程的新机制。这个 我们研究的目标是从机械上了解蛋氨酸的改变是如何转化为 生物效应。为了实现这一目标，我的实验室将建立和支持三个研究项目。 通过初步筛选，我们确定了几种促进抵抗饥饿或氧化的MT 应激类似于蛋氨酸代谢途径的操作。我将测试几种型号以确定 哪些MTS作用于蛋氨酸代谢下游，并完成其余MTS的筛选 (项目1)。其次，我将测试选定的MT的组织特异性表达是否有助于解释 利用一种新的组织特异性研究全球蛋氨酸水平变化如何影响特定MT的特异性 我们最近开发的蛋氨酸降解系统(项目2)。最后，我们将使用开放式的 蛋白质组学方法识别已识别的MT的预期下游靶点并测试这些MT如何 影响应激的功能反应(项目3)。这些平台相互交叉，但也独立工作， 注意到我们已经确定了几个促进抵抗不同压力的MT，因此项目2 和3可以独立于项目1执行。我们将通过结合 新的遗传工具，允许我们操纵特定组织内的蛋氨酸水平，并使用一种状态- 体内蛋氨酸去向的最新量化方法。这项拟议的研究意义重大，因为它将 揭示中枢代谢途径(蛋氨酸)如何控制许多基本的细胞过程。这是基本的 研究可能进一步确定与多种人类病理相关的“可下药”靶点 重新编程的蛋氨酸代谢，包括癌症、肥胖、神经变性和衰老。

PROJECT SUMMARY/ABSTRACT Methionine metabolism is a central regulator of protein synthesis, mitochondrial function, antioxidant defense, and other critical cellular processes. Tightly regulating methionine flux via the methionine metabolism pathway is essential for healthy cellular function. Not surprisingly, an imbalance in this fundamental metabolic pathway has been attributed to numerous diseases. Yet, the molecular link between alterations in methionine availability and dysregulation of downstream cellular processes remains obscure. Methionine and ATP are the sole precursors for the production of the methyl donor S-adenosylmethionine (SAM), the principal and rate- limiting methyl donor for methyltransferases (MTs), which catalyze a variety of methylation reactions via the transfer of methyl groups onto different substrates. Although reprogramming of methionine metabolism has been observed with different pathological conditions, it is not known which downstream MTs link methionine metabolism to the development of these pathological conditions and what mediates the specificity of this interaction, representing a significant knowledge gap. I hypothesize that the identification of specific MTs will reveal novel mechanisms by which methionine metabolism regulates essential cellular processes. The goal of our research is to mechanistically understand how alterations in methionine are transduced into biological effects. To accomplish this goal, my laboratory will build and sustain three research projects. Through a preliminary screen, we identified several MTs that promote resistance to starvation or oxidative stress similar to manipulations of the methionine metabolism pathway. I will test several models to determine which MTs function downstream to methionine metabolism and complete the screen of the remaining MTs (Project 1). Secondly, I will test whether the tissue-specific expression of selected MTs help explain the specificity of how global changes in methionine levels affect specific MTs using a novel tissue-specific methionine degradation system that we recently developed (Project 2). Finally, we will use an open-ended proteomics approach to identify prospective downstream targets of the identified MTs and test how these MTs affect functional responses to stress (Project 3). These platforms interdigitate but also work independently, noting that we have already identified several MTs that promote resistance to different stresses, so Projects 2 and 3 can be performed independently of Project 1. We will employ innovative approaches by combining novel genetic tools that allow us to manipulate methionine levels within specific tissues and using a state-of- the-art approach to quantify methionine fate in vivo. The proposed research is significant because it will uncover how a central metabolic pathway (methionine) controls many basic cellular processes. This basic research is likely to further identify “druggable” targets relevant to multiple human pathologies associated with reprogrammed methionine metabolism including cancer, obesity, neurodegeneration, and aging.