2017年12月14日Plant Physiology在线文章，该文章为中国农业大学孙文献课题组完成，文章介绍了激酶OsCPK4的双重功能，通过调控OsRLCK176的磷酸化状态，OsCPK4可以调节OsRLCK176的稳定或是降解，从而实现对植物免疫的精细调节。

原题目为：

The kinase OsCPK4 regulates a buffering mechanism that fine-tunes innate immunity

钙依赖性蛋白激酶OsCPK4在水稻耐盐，耐旱，植物生长和发育中发挥着重要作用。然而，在水稻免疫中，OsCPK4功能的分子机制知之甚少。在这项研究中，我们阐述了在oscpk4突变体中，由微生物相关分子模式（MAMPs）触发的氧化爆发和致病相关基因的表达显着增强。这些突变体比野生型植物更能抵抗细菌性枯萎病和真菌性疾病，表明OsCPK4负调控水稻的先天免疫。进一步鉴定了OsCPK4与类受体细胞质激酶OsRLCK176相互作用。 OsRKK176的积累受到OsCPK4的负调控。有意思的是，激酶失活的OsCPK4促进OsRLCK176的降解，并且表现出比正常的蛋白更强烈的降解。OsCPK4和OsRLCK176相互磷酸化并形成反馈回路。此外，OsCPK4和OsRLCK176的激酶活性和磷酸化有助于OsRLCK176的稳定性。这些发现表明激酶失活的OsCPK4促进OsRLCK176降解并限制植物的防御反应，而OsCPK4-OsRLCK176磷酸化的激活使OsRLCK176降解机制失效，从而增强植物免疫力。总之，本研究提出了一个由OsCPK4介导的新型防御缓冲机制，可以精细的调节水稻中由MAMP触发的免疫。

The calcium-dependent protein kinase OsCPK4 has been demonstrated to play important roles in salt and drought tolerance, plant growth and development in rice. However, little is known on molecular mechanisms underlying OsCPK4 function in rice immunity. In this study, we demonstrated that the generation of oxidative burst and pathogenesis-related gene expression triggered by microbe-associated molecular patterns (MAMPs) were significantly enhanced in the oscpk4 mutants. These mutant lines are more resistant to bacterial blight and fungal blast diseases than the wild-type plants, indicating that OsCPK4 negatively regulates innate immunity in rice. OsCPK4 was further identified to interact with a receptor-like cytoplasmic kinase OsRLCK176. OsRLCK176 accumulation is negatively regulated by OsCPK4. Interestingly, the kinase-dead OsCPK4 promotes OsRLCK176 degradation more strongly than the wild-type protein. OsCPK4 and OsRLCK176 mutually phosphorylate each other and form a feedback loop. Moreover, the kinase activity and phosphorylation of OsCPK4 and OsRLCK176 contribute to the stability of OsRLCK176. These findings indicate that the kinase-inactive OsCPK4 promotes OsRLCK176 degradation and restricts plant defenses; whereas the activation of OsCPK4-OsRLCK176 phosphorylation circuit invalidates the OsRLCK176 degradation machinery and thus enhancing plant immunity. Collectively, the study proposes a novel defense buffering mechanism mediated by OsCPK4, which fine-tunes MAMP-triggered immunity in rice.

OsCPK4的非磷酸化形式处于休眠状态，促进OsRLCK176降解，负调节水稻的植物免疫。这中降解最有可能是由泛素-蛋白酶体系统（UPS）介导的。在病原体攻击和MAMP刺激后，OsCPK4和OsRLCK176相互磷酸化并形成反馈回路，使得OsRLCK176更不易被降解，从而正调控水稻免疫力。在体内，OsRLKC176也可以被其他未知的激酶磷酸化。总之，依赖于其磷酸化状态，OsCPK4可以调节OsRLCK176的降解和积累。

每日一词

mutually

英[ˈmju:tʃuəli]

美[ˈmjuːtʃuəli]

adv. 互相地，互助; 对;

[例句]She will try to arrange a mutually convenient time and place for an interview

她会尽力安排一个双方都方便的时间和地点进行面试。