Mutual Regulation of Receptor-Like Kinase SIT1 and B 'kappa-PP2A Shapes the Early Response of Rice to Salt Stress
Mutual Regulation of Receptor-Like Kinase SIT1 and B 'kappa-PP2A Shapes the Early Response of Rice to Salt Stress
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受体样激酶 SIT1 和 B'kappa-PP2A 的相互调节塑造水稻对盐胁迫的早期反应
DOI：
10.1105/tpc.18.00706
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发表时间：
2019
期刊：
影响因子：
11.6
通讯作者：
Zhang Sheng Wei
中科院分区：
文献类型：
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作者：
Zhao Ji Long;Zhang Li Qing;Li Ning;Xu Shou Ling;Yue Zhi Liang;Zhang Lu Lu;Deng Zhi Ping;Burlingame Alma L;Sun Da Ye;Wang Zhi Yong;Sun Ying;Zhang Sheng Wei
受体样激酶SIT 1在水稻根中作为一个传感器，通过提高激酶活性传递盐胁迫信号，增强盐敏感性。在这里，我们证明了蛋白磷酸酶2A（PP 2A）调节亚基B 'κ在盐胁迫下抑制SIT 1活性。B 'κ-PP 2A通过使Thr 515/516处的激酶去磷酸化直接使SIT 1失活，Thr 515/516是活化环中盐诱导的磷酸化位点，其对SIT 1活性至关重要。B 'κ过表达抑制了表达高水平SIT 1的水稻植物的盐敏感性，从而有助于耐盐性。B 'κ以SIT 1激酶依赖性方式发挥功能。在早期盐胁迫期间，激活的SIT 1磷酸化B 'κ;这不仅增强了其与SIT 1的结合，还通过Ser 502磷酸化促进B' κ蛋白的积累。因此，通过阻断SIT 1磷酸化，B 'κ抑制并微调SIT 1活性以平衡植物生长和胁迫适应。
The receptor-like kinase SIT1 acts as a sensor in rice (Oryza sativa) roots, relaying salt stress signals via elevated kinase activity to enhance salt sensitivity. Here, we demonstrate that Protein Phosphatase 2A (PP2A) regulatory subunit B'κ constrains SIT1 activity under salt stress. B'κ-PP2A deactivates SIT1 directly by dephosphorylating the kinase at Thr515/516, a salt-induced phosphorylation site in the activation loop that is essential for SIT1 activity. B'κ overexpression suppresses the salt sensitivity of rice plants expressing high levels of SIT1, thereby contributing to salt tolerance. B'κ functions in a SIT1 kinase-dependent manner. During early salt stress, activated SIT1 phosphorylates B'κ; this not only enhances its binding with SIT1, it also promotes B'κ protein accumulation via Ser502 phosphorylation. Consequently, by blocking SIT1 phosphorylation, B'κ inhibits and fine-tunes SIT1 activity to balance plant growth and stress adaptation.