Wang Yan, Yi Yuting, Liu Cong, Zheng Heping, Huang Jian, Tian Ye, Zhang Huihui, Gao Qiang, Tang Dongying, Lin Jianzhong, Liu Xuanming
Hunan Province Key Laboratory of Plant Functional Genomics and Developmental Regulation, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha 410082, Hunan, China; College of Agriculture and Biotechnology, Hunan University of Humanities, Science and Technology, Loudi 417000, Hunan, China.
Hunan Province Key Laboratory of Plant Functional Genomics and Developmental Regulation, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha 410082, Hunan, China.
Plant Sci. 2023 Apr;329:111597. doi: 10.1016/j.plantsci.2023.111597. Epub 2023 Jan 14.
Catalase (CAT) is a vital antioxidant enzyme, while phosphorylation pivotally regulates its function. Many phosphosites have been identified in CAT, but their functions remained largely elusive. We functionally studied five phosphoserines (Ser-9, -10, -11, -18, and -205) of CatC in rice (Oryza sativa L.). Phospho-Ser-9 and - 11 and dephospho-Ser-18 promoted the enzymatic activity of CatC and enhanced oxidative and salt tolerance in yeast. Phosphorylation status of Ser-18 did not affect CatC peroxisomal targeting and stability, but dephospho-Ser-18 promoted CatC tetramerization to enhance its activity. Moreover, overexpression of dephospho-mimic form CatC in rice significantly improved the tolerance to salt and oxidative stresses by inhibiting the HO accumulation. Together, these results elucidate the mechanism underlying dephosphorylation at Ser-18 promotes CatC activity and salt tolerance in rice. Ser-18 is a promising candidate phosphosite of CatC for breeding highly salt-tolerant rice.
过氧化氢酶（CAT）是一种重要的抗氧化酶，而磷酸化对其功能起着关键的调节作用。在CAT中已鉴定出许多磷酸化位点，但其功能在很大程度上仍不清楚。我们对水稻（Oryza sativa L.）中CatC的五个磷酸化丝氨酸（Ser-9、-10、-11、-18和-205）进行了功能研究。磷酸化的Ser-9和-11以及去磷酸化的Ser-18促进了CatC的酶活性，并增强了酵母中的氧化和耐盐性。Ser-18的磷酸化状态不影响CatC向过氧化物酶体的靶向和稳定性，但去磷酸化的Ser-18促进了CatC的四聚化以增强其活性。此外，在水稻中过表达去磷酸化模拟形式的CatC通过抑制HO积累显著提高了对盐和氧化胁迫的耐受性。总之，这些结果阐明了Ser-18去磷酸化促进水稻中CatC活性和耐盐性的潜在机制。Ser-18是培育高耐盐水稻的一个有前景的CatC候选磷酸化位点。
