Ligand-induced monoubiquitination of BIK1 regulates plant immunity
Ligand-induced monoubiquitination of BIK1 regulates plant immunity
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配体诱导的BIK1单泛素化调节植物免疫
DOI：
10.1038/s41586-020-2210-3
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发表时间：
2020-04-22
期刊：
影响因子：
64.8
通讯作者：
Shan, Libo
中科院分区：
文献类型：
--
作者：
Ma, Xiyu;Claus, Lucas A. N.;Shan, Libo
植物细胞对微生物相关配体的检测激活了一个信号级联反应，在这个信号级联反应中，激酶BIK1被单双醌化，从FLS2-BAK1复合体中释放出来，并通过内吞作用被内化。模式识别受体（PRRs）对微生物相关分子模式（MAMPs）的识别触发了对入侵病原体的诱导防御的第一道防线（1-3）。受体样细胞质激酶（Receptor-like cytoplasmic kinase, RLCKs）是植物中与多个PRRs相关的趋同调节因子(4)。RLCKs激活的机制尚不清楚。在这里，我们发现当检测到MAMPs时，RLCK botrytiss诱导的激酶1 （BIK1）在磷酸化后被单素化，然后从鞭毛蛋白受体鞭毛蛋白感应2 (FLS2)-油菜素类固醇不敏感1- associated KINASE 1 （BAK1）复合体中释放出来，并动态内化到内吞室中。拟南芥E3泛素连接酶RING-H2 FINGER A3A （RHA3A）和RHA3B介导BIK1的单泛素化，这是随后从FLS2-BAK1复合体释放BIK1和激活免疫信号的必要条件。配体诱导的BIK1单泛素化和内体点表现出与PRR FLS2不同的空间和时间动态。我们的研究揭示了蛋白磷酸化和泛素化对PRR- rlck复合体激活的相互交织的调控，并表明配体诱导的单泛素化有助于从PRR复合体中释放BIK1家族RLCKs和激活PRR信号传导。
The detection of microorganism-associated ligands by plant cells activates a signalling cascade in which the kinase BIK1 is monoubiquinated, released from the FLS2-BAK1 complex, and internalized by endocytosis.Recognition of microbe-associated molecular patterns (MAMPs) by pattern recognition receptors (PRRs) triggers the first line of inducible defence against invading pathogens(1-3). Receptor-like cytoplasmic kinases (RLCKs) are convergent regulators that associate with multiple PRRs in plants(4). The mechanisms that underlie the activation of RLCKs are unclear. Here we show that when MAMPs are detected, the RLCK BOTRYTIS-INDUCED KINASE 1 (BIK1) is monoubiquitinated following phosphorylation, then released from the flagellin receptor FLAGELLIN SENSING 2 (FLS2)-BRASSINOSTEROID INSENSITIVE 1-ASSOCIATED KINASE 1 (BAK1) complex, and internalized dynamically into endocytic compartments. The Arabidopsis E3 ubiquitin ligases RING-H2 FINGER A3A (RHA3A) and RHA3B mediate the monoubiquitination of BIK1, which is essential for the subsequent release of BIK1 from the FLS2-BAK1 complex and activation of immune signalling. Ligand-induced monoubiquitination and endosomal puncta of BIK1 exhibit spatial and temporal dynamics that are distinct from those of the PRR FLS2. Our study reveals the intertwined regulation of PRR-RLCK complex activation by protein phosphorylation and ubiquitination, and shows that ligand-induced monoubiquitination contributes to the release of BIK1 family RLCKs from the PRR complex and activation of PRR signalling.