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Molecular Cell∣遗传所发文揭示调控植物免疫激酶BIK1蛋白稳...

已有 2642 次阅读 2018-1-20 21:39 |系统分类:论文交流

2018年1月18日,Molecular Cell发表了题为“A Regulatory Module Controlling Homeostasis of a Plant Immune Kinase”的文章。


该文章为中国科学院遗传与发育生物学研究所周俭民课题组完成。文章揭示了G蛋白和CPK28通过调控E3泛素连接酶PUB25和PUB26的活性来调节BIK1蛋白稳定性,进而精细调控植物的免疫反应。本研究对农作物抗病性状改良具有重要的指导意义。


动态控制免疫调节关键激酶BIK1的稳定性,对植物具有适当的免疫功能是至关重要的。本文鉴定了一对靶向BIK1的E3连接酶,PUB25和PUB26,它们与钙离子依赖蛋白激酶CPK28和异源三聚体G蛋白形成一个调节模块,促进或抑制BIK1降解,从而保持BIK1的稳态及免疫力。


摘要:

植物模式识别受体(PRRs)感知微生物和内源性分子模式以激活免疫信号。细胞质激酶BIK1在多个PRRs的下游作为限速成分起作用,其磷酸化和积累是免疫信号传播的中心。以往的研究将钙依赖性蛋白激酶CPK28和异源三聚体G蛋白分别鉴定为BIK1积累的负调控因子和正调控因子。然而,其调控机制仍然是未知的。在这里,我们的结果显示,植物U-box 蛋白PUB25和PUB26与E3连接酶同源,是BIK1降解从而负调控免疫的mark。我们证明异三聚体G蛋白抑制PUB25/26活性来稳定BIK1,而CPK28特异性磷酸化PUB25/26中的保守残基以增强它们的活性并促进BIK1降解。有趣的是,PUB25/26特异性靶向未激活的BIK1,表明活性BIK1可以维持免疫信号传导。我们的研究结果揭示了一个多蛋白质调控模块,从而强大而紧密调节免疫反应。


Abstract:

Plant pattern recognition receptors (PRRs) perceive microbial and endogenous molecular patterns to activate immune signaling. The cytoplasmic kinase BIK1 acts downstream of multiple PRRs as a rate-limiting component, whose phosphorylation and accumulation are central to immune signal propagation. Previous work identified the calcium-dependent protein kinase CPK28 and heterotrimeric G proteins as negative and positive regulators of BIK1 accumulation, respectively. However, mechanisms underlying this regulation remain unknown. Here we show that the plant U-box proteins PUB25 and PUB26 are homologous E3 ligases that mark BIK1 for degradation to negatively regulate immunity. We demonstrate that the heterotrimeric G proteins inhibit PUB25/26 activity to stabilize BIK1, whereas CPK28 specifically phosphorylates conserved residues in PUB25/26 to enhance their activity and promote BIK1 degradation. Interestingly, PUB25/26 specifically target non-activated BIK1, suggesting that activated BIK1 is maintained for immune signaling. Our findings reveal a multi-protein regulatory module that enables robust yet tightly regulated immune responses.







https://blog.sciencenet.cn/blog-634883-1095946.html

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