eIF2B (eukaryotic initiation factor 2B): regulation of its activity and expression, and its roles in translation initiation

eIF2B（真核起始因子 2B）：其活性和表达的调节及其在翻译起始中的作用

• 批准号: BB/J007706/1
• 负责人: Christopher Proud
• 金额: $ 78.57万
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2012
• 资助国家: 英国
• 起止时间: 2012 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FJ007706%2F1
• 关键词: eIF2B; eukaryotic; initiation; factor; 2B

The production of proteins is a key process in all living cells, allowing them to use the genetic information held in the genes in their DNA. Most genes contain the information for making proteins, which are the cellular components that carry out almost all the functions of the cell. To make the protein coded for by a given gene, the letters in the DNA are first copied to a second similar molecule, known as mRNA, in a process called transcription. This mRNA molecule is then 'read' by molecular machines called ribosomes in order to produce the protein, a process known as translation. The proteins expressed within a cell determine its properties, e.g., how it will function and respond to its environment. The process of protein synthesis consumes a large proportion of a cell's energy and nutrients, and so it must be very tightly controlled. Furthermore, this process can be altered to favour the production of different proteins by allowing the machinery to preferentially 'read' certain mRNA molecules, which therefore allows the cell to respond quickly to a stressful environment caused, for example, by a reduction in available nutrients or energy. This kind of mechanism can also control the expression of different proteins as a cell goes through its stages of growth and division, the cell cycle. A key part of the control of protein synthesis involves proteins termed 'initiation factors', which are the focus of this research. These initiation factors control the attachment of the mRNA molecules to ribosomes and are vital to allow protein synthesis to start. They are also a key point of regulation under a wide variety of conditions because they control which mRNA molecules to recruit and even exactly where to start reading their code. The main focus of this research is a factor termed eIF2B, which is composed of 5 separate protein 'subunits'. We will also study two proteins that work with eIF2B in the process of protein synthesis, eIF2 and ABC50. The applicant's laboratory has many years' experience in investigating all these proteins.Disruption of the normal function of eIF2B can lead to disease. Slight spelling mistakes in the genes that encode the 5 subunits of eIF2B lead to an often-serious brain disease, known as 'vanishing white matter'. It also responds to insulin, and so is mis-regulated in type I (insulin-dependent) diabetes. This implies that the proper functioning of eIF2B is necessary to maintain a healthy cell. Furthermore, eIF2B, eIF2 and ABC50 limit the capacity of cells to make proteins that are used as drugs or in disease diagnosis, and which are of great commercial value.We aim to study four main aspects of eIF2B:1. How it is controlled, based on new discoveries made by the applicant's laboratory or others, to learn more about how this important protein can be controlled under different conditions in the cell;2. How cells can control how much of this protein they contain, and how this is related to the control of the amounts of eIF2 and ABC50: this is important as changes in the amounts of all these proteins will affect both how fast proteins can be made and how protein production is controlled;3. How changes in the amounts or the cellular activity of eIF2B (and ABC50) affect the production of specific proteins. This is important since, as described above, changes in protein synthesis have a major affect on how much of different proteins are present in cells, and thus on the function and 'health' of the cell;4. Its structure, using state-of-the-art techniques to investigate the way in which its five subunits are arranged and how they interact with its partner protein, eIF2.

蛋白质的生产是所有活细胞的关键过程，使它们能够利用DNA中的基因中包含的遗传信息。大多数基因都含有制造蛋白质的信息，蛋白质是执行细胞几乎所有功能的细胞成分。为了使特定基因编码的蛋白质，DNA中的字母首先被复制到第二个类似的分子，称为信使核糖核酸，在一个称为转录的过程中。然后，这种信使核糖核酸分子被称为核糖体的分子机器读取，以产生蛋白质，这一过程被称为翻译。细胞内表达的蛋白质决定其性质，例如，它将如何发挥作用和对环境做出反应。蛋白质合成过程消耗了细胞很大比例的能量和营养，因此必须非常严格地加以控制。此外，这一过程可以改变为有利于不同蛋白质的产生，方法是允许机器优先读取特定的信使核糖核酸分子，从而允许细胞对应激环境做出快速反应，例如，可用营养或能量的减少。这种机制还可以控制细胞在生长和分裂阶段以及细胞周期中不同蛋白质的表达。控制蛋白质合成的一个关键部分涉及被称为“起始因子”的蛋白质，这是本研究的重点。这些起始因子控制着信使核糖体分子与核糖体的结合，对蛋白质合成的启动至关重要。在各种各样的条件下，它们也是一个关键的调节点，因为它们控制着招募哪些信使核糖核酸分子，甚至从哪里开始阅读它们的密码。本研究的重点是一个名为eIF2B的因子，它由5个独立的蛋白质‘亚基’组成。我们还将研究在蛋白质合成过程中与eIF2B一起工作的两种蛋白质，eIF2和ABC50。申请人的实验室在研究所有这些蛋白质方面有多年的经验。eIF2B的正常功能中断可能会导致疾病。编码eIF2B 5个亚基的基因稍有拼写错误，就会导致一种通常很严重的脑部疾病，也就是我们所知的“脑白质消失”。它对胰岛素也有反应，因此在I型(胰岛素依赖型)糖尿病中调节不当。这意味着eIF2B的正常功能对于维持一个健康的细胞是必要的。此外，eIF2B、eIF2和ABC50限制了细胞制造用于药物或疾病诊断的具有巨大商业价值的蛋白质的能力。我们的目标是研究eIF2B的四个主要方面：1.根据申请人的实验室或其他人的新发现，它是如何被控制的，以了解如何在不同的细胞条件下控制这种重要的蛋白质；2.细胞如何控制其含有多少这种蛋白质，这与eIF2和ABC50的数量控制有何关系：这一点很重要，因为所有这些蛋白质的数量的变化将影响蛋白质制造的速度和蛋白质生产的控制方式；3.eIF2B(和ABC50)的数量或细胞活动的变化如何影响特定蛋白质的产生。这一点很重要，因为如上所述，蛋白质合成的变化对细胞中存在多少不同的蛋白质有重大影响，从而影响细胞的功能和健康；4.其结构，使用最先进的技术研究其五个亚基的排列方式，以及它们如何与其伙伴蛋白质eIF2相互作用。

项目成果

ABC50 mutants modify translation start codon selection.

ABC50 突变体修改翻译起始密码子选择。

• DOI: 10.1042/bj20141453
• 发表时间: 2015
• 期刊: The Biochemical journal
• 作者: Stewart JD

eIF2B: recent structural and functional insights into a key regulator of translation.

eIF2B：最近对翻译关键调节因子的结构和功能见解。

• DOI: 10.1042/bst20150164
• 发表时间: 2015
• 期刊: Biochemical Society transactions
• 影响因子: 3.9
• 作者: Wortham NC

Biochemical effects of mutations in the gene encoding the alpha subunit of eukaryotic initiation factor (eIF) 2B associated with Vanishing White Matter disease.

• DOI: 10.1186/s12881-015-0204-z
• 发表时间: 2015-08-19
• 期刊: BMC medical genetics
• 作者: Wortham NC;Proud CG
• 通讯作者: Proud CG