Phosphorylation and ubiquitination of immune sensory complexes in innate immune signaling

天然免疫信号中免疫感觉复合体的磷酸化和泛素化 项目摘要 植物和动物依靠模式识别受体(PRRs)通过识别相关微生物来检测感染 分子模式(MAMP)。Fls2是哺乳动物Toll样受体(TLRs)在植物中的结构和功能同源基因， 识别细菌鞭毛蛋白，并通过与辅助受体BAK1二聚化来启动免疫信号。使用以前的 在NIH的支持下，我们已经鉴定出一个质膜拴系的受体样胞浆激酶(RLCK)BIK1 通过与多个PRR复合体结合而形成的聚合型免疫调节剂。MAMP知觉诱导快速BIK1 被BAK1磷酸化，随后从PRR复合体释放，转导不同的免疫信号。它仍然存在 未知与PRR相关的BIK1如何被激活，然后将细胞内的PRR信号分成两个分支。我们的初步数据 表明MAMP感知触发了BIK1及其相关RLKs的快速单一泛素化。一种环型E3泛素 连接酶BMU1被BIK1磷酸化，介导MAMP诱导的BIK1泛素化。BIK1相互作用并 磷酸化调节MAMP诱导的磷脂酸(PA)产生的二酰基甘油激酶DGK5。三 最重要的目的是检验一个中心假设，即BMU1对BIK1的单一泛素化会触发BK1的释放 来自PRR复合体的BIK1，以及随后的内体运输和转导细胞内信号事件，包括 DGK5的激活用于PA生产。 三个具体目标是 1.BIK1磷酸化的BMU1在植物免疫中泛素化； 2.配体诱导的BIK1单一泛素化在内体转运和植物免疫中的作用； 3.PRR激活的BIK1和MAPK4在植物免疫中对DGK5的双重磷酸化。 非我识别的分子结构的最新进展揭示了在非我识别中的显著保守性 多细胞真核生物中微生物感知和先天免疫信号的机制。磷酸化和 泛素化是调节不同细胞和生物过程的两个关键机制。我们的病原体研究项目- 诱导的顺序和缠绕的磷酸化和泛素化协调PRR复合体的激活和信号 植物免疫中的转导将在理解这两种生物功能方面产生概念上的进步 整个生物体层面的普遍调控机制。拟议的研究也将有助于一般 了解先天免疫信号和免疫感觉复合体功能。

Phosphorylation and ubiquitination of immune sensory complexes in innate immune signaling Project Summary Plants and animals rely on pattern-recognition receptors (PRRs) to detect infection by recognizing microbe-associated molecular patterns (MAMPs). FLS2, a structural and functional ortholog of mammalian Toll-like receptors (TLRs) in plants, recognizes bacterial flagellin and initiates immune signaling by dimerizing with a co-receptor BAK1. With the previous NIH support, we have identified a plasma membrane-tethered receptor-like cytoplasmic kinase (RLCK) BIK1 as a convergent immune regulator by association with multiple PRR complexes. MAMP perception induces rapid BIK1 phosphorylation by BAK1, and subsequent release from PRR complexes to transduce diverse immune signaling. It remains unknown how PRR-associated BIK1 is activated and then bifurcates intracellular PRR signaling. Our preliminary data indicate that MAMP perception triggers rapid mono-ubiquitination of BIK1 and related RLCKs. A RING-type E3 ubiquitin ligase BMU1, that is phosphorylated by BIK1, mediates MAMP-induced BIK1 ubiquitination. BIK1 interacts and phosphorylates a diacylglycerol kinase DGK5 that regulates MAMP-induced phosphatidic acid (PA) production. Three over-arching aims are proposed to test a central hypothesis that mono-ubiquitination of BIK1 by BMU1 triggers release of BIK1 from PRR complexes, and subsequent endosomal trafficking and relaying intracellular signaling events, including activation of DGK5 for PA production. Three specific aims are 1. Ubiquitination of BIK1 by BIK1-phosphorylated BMU1 in plant immunity; 2. Ligand-induced BIK1 mono-ubiquitination in endosomal trafficking and plant immunity; 3. Dual phosphorylation of DGK5 by PRR-activated BIK1 and MAP kinase 4 in plant immunity. Recent advance on the molecular architecture of nonself recognition has revealed remarkable conservation in the mechanisms of microbial perception and innate immune signaling in multicellular eukaryotes. Phosphorylation and ubiquitination are two key mechanisms in regulating diverse cellular and organismal processes. Our project on pathogen- induced sequential and intertwined phosphorylation and ubiquitination orchestrating PRR complex activation and signal transduction in plant immunity will generate conceptual advance in understanding the biological functions of these two universal regulatory mechanisms at the whole organismal level. The proposed research will also contribute to the general understanding of innate immune signaling and immune sensory complex function.