School of Biological and Biomedical Sciences, Durham University, Durham, DH1 3HP, UK.
The Scottish Institute for Cell Signalling (SCILLS), Sir James Black Centre, University of Dundee, Dundee, DD1 5EH, UK.
New Phytol. 2012 Oct;196(1):13-28. doi: 10.1111/j.1469-8137.2012.04266.x. Epub 2012 Aug 16.
Ubiquitin is well established as a major modifier of signalling in eukaryotes. However, the extent to which plants rely on ubiquitin for regulating their lifecycle is only recently becoming apparent. This is underlined by the over-representation of genes encoding ubiquitin-metabolizing enzymes in Arabidopsis when compared with other model eukaryotes. The main characteristic of ubiquitination is the conjugation of ubiquitin onto lysine residues of acceptor proteins. In most cases the targeted protein is rapidly degraded by the 26S proteasome, the major proteolysis machinery in eukaryotic cells. The ubiquitin-proteasome system is responsible for removing most abnormal peptides and short-lived cellular regulators, which, in turn, control many processes. This allows cells to respond rapidly to intracellular signals and changing environmental conditions. This review maps out the roles of the components of the ubiquitin-proteasome system with emphasis on areas where future research is urgently needed. We provide a flavour of the diverse aspects of plant lifecycle where the ubiquitin-proteasome system is implicated. We aim to highlight common themes using key examples that reiterate the importance of the ubiquitin-proteasome system to plants. The future challenge in plant biology is to define the targets for ubiquitination, their interactors and their molecular function within the regulatory context.
泛素是真核生物信号转导的主要调节剂。然而，植物在多大程度上依赖泛素来调节其生命周期，这在最近才变得明显。与其他模式真核生物相比，拟南芥中编码泛素代谢酶的基因的过度表达就强调了这一点。泛素化的主要特征是将泛素连接到靶蛋白的赖氨酸残基上。在大多数情况下，靶蛋白被 26S 蛋白酶体（真核细胞中主要的蛋白水解机制）迅速降解。泛素-蛋白酶体系统负责去除大多数异常肽和寿命短的细胞调节剂，而这些调节剂反过来又控制着许多过程。这使得细胞能够快速响应细胞内信号和不断变化的环境条件。本综述概述了泛素-蛋白酶体系统组件的作用，并重点介绍了未来急需研究的领域。我们提供了植物生命周期中泛素-蛋白酶体系统所涉及的各个方面的概述。我们旨在通过反复强调泛素-蛋白酶体系统对植物的重要性，用关键实例来突出主题。植物生物学的未来挑战是确定泛素化的靶标、它们的相互作用物及其在调节背景下的分子功能。
