State Key Laboratory of Plant Genomics, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, Hebei, 050021, China.
Joint Center for Single Cell Biology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China.
Nat Commun. 2023 Aug 2;14(1):4624. doi: 10.1038/s41467-023-40364-0.
Pathogen-associated molecular patterns (PAMPs) trigger plant innate immunity that acts as the first line of inducible defense against pathogen infection. A receptor-like cytoplasmic kinase BOTRYTIS-INDUCED KINASE 1 (BIK1) functions as a signaling hub immediately downstream of multiple pattern recognition receptors (PRRs). It is known that PLANT U-BOX PROTEIN 25 (PUB25) and PUB26 ubiquitinate BIK1 and mediate BIK1 degradation. However, how BIK1 homeostasis is maintained is not fully understood. Here, we show that two closely related ubiquitin ligases, RING DOMAIN LIGASE 1 (RGLG1) and RGLG2, preferentially associate with the hypo-phosphorylated BIK1 and promote the association of BIK1 with the co-receptor for several PRRs, BRI1-ASSOCIATED RECEPTOR KINASE1 (BAK1). PUB25 interacts with RGLG2 and mediates its degradation. In turn, RGLG2 represses the ubiquitin ligase activity of PUB25. RGLG1/2 suppress PUB25-mediated BIK1 degradation, promote BIK1 protein accumulation, and positively regulate immune signaling in a ubiquitin ligase activity-dependent manner. Our work reveals how BIK1 homeostasis is maintained by the interplay of different ubiquitin ligases.
病原体相关分子模式（PAMPs）触发植物先天免疫，作为对病原体感染的诱导防御的第一道防线。一种受体样细胞质激酶 BRYOTIS-INDUCED KINASE 1（BIK1）作为多个模式识别受体（PRRs）的下游信号枢纽发挥作用。已知 PLANT U-BOX PROTEIN 25（PUB25）和 PUB26 泛素化 BIK1 并介导 BIK1 降解。然而，BIK1 动态平衡是如何维持的还不完全清楚。在这里，我们表明两个密切相关的泛素连接酶，RING DOMAIN LIGASE 1（RGLG1）和 RGLG2，优先与低磷酸化的 BIK1 结合，并促进 BIK1 与几个 PRRs 的共受体 BRYOTIS-ASSOCIATED RECEPTOR KINASE1（BAK1）的结合。PUB25 与 RGLG2 相互作用并介导其降解。反过来，RGLG2 抑制 PUB25 的泛素连接酶活性。RGLG1/2 抑制 PUB25 介导的 BIK1 降解，促进 BIK1 蛋白积累，并以依赖泛素连接酶活性的方式正向调节免疫信号。我们的工作揭示了不同的泛素连接酶如何相互作用来维持 BIK1 的动态平衡。
Zotero 插件
