21ENGBIO - Converting a cellular dustbin into a protein storing organelle

21ENGBIO - 将细胞垃圾箱转变为蛋白质储存细胞器

• 批准号: BB/W012162/1
• 负责人: Lorenzo Frigerio
• 金额: $ 12.71万
• 依托单位: University of Warwick
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FW012162%2F1
• 关键词: 21ENGBIO; Converting; cellular; dustbin; into

Plants feed the world. Most proteins eaten by humans and animals come (either directly or indirectly) from plants, in particular seeds. Plant seed proteins are synthesised in the secretory pathway - a system of cellular membranes that comprises the endoplasmic reticulum, the Golgi complex, endosomal compartments, and the vacuole. Plant seed cells store proteins in the endoplasmic reticulum, the vacuole, or both. The protein storage vacuole (PSV) is the preferred storage site in dicotyledonous plants such as legumes and is the main nutritional repository underpinning seed consumption. Plants are also increasingly used as hosts to produce high value pharmaceutical proteins, including, recently, a vaccine against COVID-19. The main challenge is to ensure that plant-produced proteins are accumulated and stored stably. In non-seed cells, the vacuole normally provides a harsh environment, serving a degradative (lytic) function in most plant tissues (akin to the lysosome in animal cells). Early attempts to express individual seed proteins, or high-value proteins such as antibodies, into the vacuoles of transgenic leaf cells led to the proteins to be degraded over time. In this project we propose to test a starteg to turn lytic vacuoles into protein storage vacuoles. In the last 5 years we have studied how PSV are formed during seed maturation: in seed embryo cells, there is a single lytic vacuole, which during maturation becomes filled with storage proteins and then divides to form multiple, protein-laden PSV. Very recently we have discovered that the seed storage proteins form a separate liquid phase inside the vacuole, which creates dense droplets; these droplets interact with the membrane of the vacuole and cause it to bend, forming buds; the buds eventually separate to form many PSV. We therefore hypothesise that this physical process of protein droplet formation, called liquid-liquid phase separation (LLPS), is the key driver of the transition from a lytic vacuole to a storage vacuole. This is very exciting: if our hypothesis is correct, we will be able to induce this process to convert lytic vacuoles, both in plant non-seed tissues (such as leaves), and in non-plant organisms, such as yeast, into protein-storing organelles. In this project we will test our hypothesis by expressing a panel of seed storage proteins, and other proteins which are known to undergo LLPS, in plant leaves and in yeast. We will therefore be able to establish which proteins are the most suitable for triggering the lytic-to-storage vacuole conversions. Therefore we will provide both the proof of principle and the blueprint for re-purposing cellular 'dustbins' into protein-storing compartments for high value protein contents.

植物养活世界。大多数由人类和动物食用的蛋白质（直接或间接）来自植物，特别是种子。植物种子蛋白在分泌途径中合成 - 一种包括内质网，高尔基体复合物，内体隔室和液泡的细胞膜系统。植物种子细胞将蛋白质储存在内质网中，液泡或两者兼而有之。蛋白质存储液泡（PSV）是豆科植物（例如豆科植物）中首选的存储位点，是基于种子消耗的主要营养存储库。植物也越来越多地用作宿主，以产生高价值的药物蛋白，包括最近针对Covid-19的疫苗。主要的挑战是确保积累植物生产的蛋白质并稳定储存。在非种子细胞中，液泡通常提供一个严酷的环境，在大多数植物组织（类似于动物细胞中的溶酶体）中具有降解（裂解）功能。早期尝试表达单个种子蛋白或高价值蛋白（例如抗体）进入转基因叶细胞的液泡导致蛋白质随着时间的推移而降解。在这个项目中，我们建议测试一个开始的裂解液泡变成蛋白质储存液泡。在过去的五年中，我们研究了在种子成熟过程中如何形成PSV：在种子胚细胞中，有一个单个裂解液泡，在成熟过程中，该液泡填充有储存蛋白，然后分裂以形成多个含有蛋白质的PSV。最近，我们发现种子储存蛋白在液泡内形成一个单独的液相，从而产生致密的液滴。这些液滴与液泡的膜相互作用，并导致其弯曲，形成芽。芽最终分开以形成许多PSV。因此，我们假设这种蛋白质液滴形成的物理过程称为液 - 液相分离（LLP），是从裂解液泡到存储液泡的过渡的关键驱动力。这是非常令人兴奋的：如果我们的假设正确，我们将能够在植物非种子组织（例如叶子）和非植物生物（例如酵母）中诱导这种过程转化裂解液泡，以转化为蛋白质储存的细胞器中。在这个项目中，我们将通过表达一系列种子储存蛋白和其他已知会在植物叶和酵母中经历LLP的蛋白质来检验我们的假设。因此，我们将能够确定哪种蛋白质最适合触发裂解到储存液泡转换。因此，我们将同时提供原理证明和蓝图，以将细胞的“尘土”重新定位为高价值蛋白质含量的蛋白质存储室。