Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064, China.
Department of Genetics, Development, and Cell Biology, Plant Sciences Institute, Iowa State University, Ames, Iowa 50011, USA.
Plant Cell. 2022 Oct 27;34(11):4516-4530. doi: 10.1093/plcell/koac245.
BRI1-EMS-SUPPRESSOR1 (BES1), a core transcription factor in the brassinosteroid (BR) signaling pathway, primarily regulates plant growth and development by influencing BR-regulated gene expression. Several E3 ubiquitin (Ub) ligases regulate BES1 stability, but little is known about BES1 deubiquitination, which antagonizes E3 ligase-mediated ubiquitination to maintain BES1 homeostasis. Here, we report that two Arabidopsis thaliana deubiquitinating enzymes, Ub-SPECIFIC PROTEASE (UBP) 12 and UBP13, interact with BES1. UBP12 and UBP13 removed Ub from polyubiquitinated BES1 to stabilize both phosphorylated and dephosphorylated forms of BES1. A double mutant, ubp12-2w ubp13-3, lacking UBP12 and UBP13 function showed both BR-deficient and BR-insensitive phenotypes, whereas transgenic plants overexpressing UBP12 or UBP13 exhibited an increased BR response. Expression of UBP12 and UPB13 was induced during recovery after carbon starvation, which led to BES1 accumulation and quick recovery of stressed plants. Our work thus establishes a mechanism by which UBP12 and UBP13 regulate BES1 protein abundance to enhance BR-regulated growth during recovery after carbon starvation.
BRI1-EMS-SUPPRESSOR1（BES1）是油菜素内酯（BR）信号通路中的核心转录因子，主要通过影响 BR 调节基因的表达来调节植物的生长和发育。几种 E3 泛素（Ub）连接酶调节 BES1 的稳定性，但对 BES1 的去泛素化知之甚少，去泛素化拮抗 E3 连接酶介导的泛素化，以维持 BES1 的内稳态。在这里，我们报告两个拟南芥去泛素化酶，Ub-SPECIFIC PROTEASE（UBP）12 和 UBP13，与 BES1 相互作用。UBP12 和 UBP13 从多泛素化 BES1 上去除 Ub，以稳定磷酸化和去磷酸化形式的 BES1。缺乏 UBP12 和 UBP13 功能的双突变体 ubp12-2w ubp13-3 表现出 BR 缺陷和 BR 不敏感表型，而过表达 UBP12 或 UBP13 的转基因植物表现出增强的 BR 反应。在碳饥饿恢复期间，UBP12 和 UPB13 的表达被诱导，导致 BES1 积累和受胁迫植物的快速恢复。因此，我们的工作建立了一个机制，即 UBP12 和 UBP13 调节 BES1 蛋白丰度，以增强 BR 调节的碳饥饿恢复后的生长。
