Yang Heng, Zhang Yi, Lyu Shanwu, Mao Yaping, Yu Fangqin, Liu Sai, Fang Yujie, Deng Shulin
Guangdong Provincial Key Laboratory of Applied Botany & Key Laboratory of National Forestry and Grassland Administration on Plant Conservation and Utilization in Southern China, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
J Integr Plant Biol. 2025 May;67(5):1274-1289. doi: 10.1111/jipb.13845. Epub 2025 Jan 28.
Reactive oxygen species (ROS) plays critical roles in modulating plant growth and stress response and its homeostasis is fine tuned using multiple peroxidases. HO, a major kind of ROS, is removed rapidly and directly using three catalases, CAT1, CAT2, and CAT3, in Arabidopsis. Although the activity regulations of catalases have been well studied, their degradation pathway is less clear. Here, we report that CAT2 and CAT3 protein abundance was partially controlled using the 26S proteasome. To further identify candidate proteins that modulate the stability of CAT2, we performed yeast-two-hybrid screening and recovered several clones encoding a protein with RING and vWA domains, CIRP1 ( CAT2 Interacting RING Protein 1). Drought and oxidative stress downregulated CIRP1 transcripts. CIRP1 harbored E3 ubiquitination activity and accelerated the degradation of CAT2 and CAT3 by direct interaction and ubiquitination. The cirp1 mutants exhibited stronger drought and oxidative stress tolerance, which was opposite to the cat2 and cat3 mutants. Genetic analysis revealed that CIRP1 acts upstream of CAT2 and CAT3 to negatively regulate drought and oxidative stress tolerance. The increased drought and oxidative stress tolerance of the cirp1 mutants was due to enhanced catalase (CAT) activities and alleviated ROS levels. Our data revealed that the CIRP1-CAT2/CAT3 module plays a vital role in alleviating ROS levels and balancing growth and stress responses in Arabidopsis.
活性氧(ROS)在调节植物生长和胁迫反应中起关键作用,其稳态通过多种过氧化物酶进行精细调节。在拟南芥中,主要的活性氧种类H₂O₂可通过三种过氧化氢酶CAT1、CAT2和CAT3迅速直接清除。尽管过氧化氢酶的活性调节已得到充分研究,但其降解途径尚不清楚。在此,我们报道CAT2和CAT3的蛋白质丰度部分受26S蛋白酶体调控。为进一步鉴定调节CAT2稳定性的候选蛋白,我们进行了酵母双杂交筛选,并获得了几个编码具有RING和vWA结构域的蛋白CIRP1(CAT2相互作用RING蛋白1)的克隆。干旱和氧化胁迫下调了CIRP1的转录本。CIRP1具有E3泛素化活性,并通过直接相互作用和泛素化加速CAT2和CAT3的降解。cirp1突变体表现出更强的干旱和氧化胁迫耐受性,这与cat2和cat3突变体相反。遗传分析表明,CIRP1在CAT2和CAT3上游起作用,负向调节干旱和氧化胁迫耐受性。cirp1突变体干旱和氧化胁迫耐受性增强是由于过氧化氢酶(CAT)活性增强和活性氧水平降低。我们的数据表明,CIRP1-CAT2/CAT3模块在减轻拟南芥活性氧水平以及平衡生长和胁迫反应中起重要作用。