Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH16 5JF, U.K.
Essays Biochem. 2022 Aug 5;66(2):111-121. doi: 10.1042/EBC20210094.
Ubiquitination is an essential post-translational signal that allows cells to adapt and respond to environmental stimuli. Substrate modifications range from a single ubiquitin molecule to complex polyubiquitin chains, where diverse chain topologies constitute a code that is utilized to modify the functions of proteins in numerous cellular signalling pathways. Diverse ubiquitin chain topologies are generated by linking the C-terminus of ubiquitin to one of seven lysine residues or the N-terminal methionine 1 residue of the preceding ubiquitin. Cooperative action between a large array of E2 conjugating and E3 ligase enzymes supports the formation of not only homotypic ubiquitin chains but also heterotypic mixed or branched chains. This complex array of chain topologies is recognized by proteins containing linkage-specific ubiquitin-binding domains and regulates numerous cellular pathways. Although many functions of the ubiquitin code in plants remain unknown, recent work suggests that specific chain topologies are associated with particular molecular processes. Deciphering the ubiquitin code and how plants utilize it to cope with the changing environment is essential to understand the regulatory mechanisms that underpin myriad stress responses and establishment of environmental tolerance.
泛素化是一种重要的翻译后信号，使细胞能够适应和响应环境刺激。底物修饰范围从单个泛素分子到复杂的多泛素链，其中不同的链拓扑结构构成了一种用于修饰众多细胞信号通路中蛋白质功能的密码。通过将泛素的 C 末端连接到泛素的七个赖氨酸残基之一或前一个泛素的 N 末端甲硫氨酸 1 残基，可产生不同的泛素链拓扑结构。大量 E2 连接酶和 E3 连接酶的协同作用不仅支持同型泛素链的形成，还支持异型混合或分支链的形成。含有特定连接泛素结合域的蛋白质识别这种复杂的链拓扑结构，并调节许多细胞途径。尽管植物中泛素密码的许多功能仍然未知，但最近的研究表明，特定的链拓扑结构与特定的分子过程相关。破译泛素密码以及植物如何利用它来应对不断变化的环境对于理解支持众多应激反应和建立环境耐受性的调控机制至关重要。
