13 ERA-CAPS PER-ASPERA Frigerio

植物内膜系统支撑着植物生命的几乎每一个方面，并为我们每一个人提供食物，因为它是生产动物和人类营养所需的蛋白质和脂质的“工厂”。它是细胞内相互连接的、以膜为界的隔室系统，形成称为分泌途径的代谢连续体。一个主要的组成部分是内质网（ER），它是分泌途径的入口。ER是一种管状膜网络，参与蛋白质的合成、组装、质量控制和向分泌途径的其他隔室的输出。ER也是合成脂质的主要位点，存在于所有真核生物中，但在植物细胞中具有独特的功能：它可以作为蛋白质（如玉米种子）和脂质（如向日葵等油料作物）的储存室。ER是一个非常动态的结构，可以改变其形状以适应这些不同的功能。然而，我们不知道为什么ER的独特结构对其功能是必要的。目前还不清楚调节植物内质网形状的因素，以及它的形状如何决定内质网可以合成和/或储存多少蛋白质和脂质。在过去的5年里，我们在可能有助于调节这一重要结构的组织的机制上取得了一些重要的发现。我们已经发现，一个名为reticulons的蛋白质家族可以诱导植物ER网络形状的变化，从而影响其功能。我们还鉴定了一些蛋白质，它们是作为ER网络分支、小管融合和锚定的调节剂的良好候选物。为了帮助我们的研究，我们开发了一个计算机化的映射系统，用于分析ER的动态。从本质上讲，我们现在知道了构建ER架构所需的成分。我们还不知道的是这些成分是如何结合在一起来决定它的。在这个跨国项目中，我们建议调查的性质和相互作用的蛋白质的锚ER网络到其他细胞器，和蛋白质，允许新的ER小管形成，生长和融合与现有的小管。我们将研究如何改变这些蛋白质的表达影响脂质储存蛋白的合成和运输，特别是在谷物种子。了解这些关键调控因子的功能将使我们能够重新设计ER，以提高其在种子作物中制造蛋白质和脂质的能力。

The plant endomembrane system underpins virtually every aspect of plant life and feeds every one of us, because it is the 'factory' where proteins and lipids for animal and human nutrition are produced. It is a system of interconnected, membrane-bounded compartments within the cell, forming a metabolic continuum called the secretory pathway. A major component is the endoplasmic reticulum (ER), which is the port of entry of the secretory pathway. The ER is a network of tubular membranes involved in the synthesis, assembly, quality control and export of proteins to other compartments of the secretory pathway. The ER is also a major site for the synthesis of lipids and is present in all eukaryotes, but has unique features in plant cells: it can act as a storage compartment for proteins (like in maize seeds) and lipids (like in oilseed crops such as sunflower). The ER is a very dynamic structure and can change its shape in order to accommodate these diverse functions. However, we do not know why the unique architecture of the ER is necessary for its function. Nothing is known about the factors that regulate plant ER shape and how its shape determines how much protein and lipid the ER can synthesise and/or store. Over the past 5 years we have made some important discoveries on the mechanisms that may help regulate the organisation of this important structure. We have discovered that a family of proteins called reticulons can induce changes in the shape of the plant ER network, thereby affecting its function. Also we have identified some proteins which are good candidates as regulators of ER network branching, tubule fusions and anchoring. To help our studies, we have contributed to developing a computerised mapping system for analysing the dynamics of the ER. In essence, we now know the ingredients required to build the architecture of the ER. What we don't yet know is how these ingredients come together to determine it.In this transnational project, we propose to investigate the nature and interactions of the proteins that anchor the ER network to other organelles, and the proteins that permit new ER tubules to form, to grow and fuse with existing tubules. We will study how changing the expression of these proteins affects the synthesis and transport of lipid storage proteins, especially in cereal seeds. Understanding the function of these key regulators will allow us to redesign the ER in order to improve its capacity to make proteins and lipids in seed crops.