The tomato Prf complex is a molecular trap for bacterial effectors based on Pto transphosphorylation.
The tomato Prf complex is a molecular trap for bacterial effectors based on Pto transphosphorylation.
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DOI：
10.1371/journal.ppat.1003123
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发表时间：
2013-01
期刊：
影响因子：
6.7
通讯作者：
Rathjen JP
中科院分区：
文献类型：
--
作者：
Ntoukakis V;Balmuth AL;Mucyn TS;Gutierrez JR;Jones AM;Rathjen JP
植物病原细菌的主要毒力策略是分泌效应蛋白进入宿主细胞，靶向免疫机制。AvrPto和AvrPtoB是来自假单胞菌的两种这样的效应子，其使拟南芥和番茄中的重叠范围的激酶失活。这两种效应物都靶向表面定位的受体激酶以避免细菌识别。反过来，番茄已经进化出由NB-LRR蛋白Prf和Pto激酶组成的细胞内效应器识别复合物。结构分析表明，AvrPto和AvrPtoB最重要的相互作用表面是Pto P+1环。AvrPto是Pto激酶活性的抑制剂，但矛盾的是，这种激酶活性是AvrPto激活防御的先决条件。在这里，使用生物化学方法，我们表明，中断Pto P+1环刺激磷酸化的反式，这是可能的，因为Pto/Prf复合物是寡聚体。P+1环的破坏和转磷酸化都是信号传导所必需的。因此，复合物中一个激酶分子的效应扰动激活另一个。因此，Pto/Prf复合物是针对靶向蛋白激酶的效应物的复杂分子陷阱，这是病原体毒力策略的重要方面。这里提供的数据清楚地说明了为什么细菌毒力和宿主识别机制经常相关，以及缓慢进化的宿主如何能够跟上快速进化的病原体。细菌假单胞菌是许多作物的病原菌，也是研究植物和细菌军备竞赛协同进化的模式病原菌之一。在目前的模型中，植物通过质膜受体感知细菌病原体，识别导致激活一般防御。反过来，细菌将称为效应子的蛋白质注入植物细胞，以防止免疫反应的激活。AvrPto和AvrPtoB是抑制多种植物激酶的两种这样的蛋白。番茄植物通过细胞质抗性复合体的进化对这些效应物作出反应。该复合物由两种蛋白质Prf和Pto激酶组成，能够识别效应蛋白。Pto激酶如何能够避免效应蛋白的抑制目前尚不清楚。我们的数据显示了番茄植物如何利用抗性蛋白的二聚化来获得对更快进化的细菌病原体的优势。在这里，我们说明，Prf的寡聚化带来了接近两个Pto激酶，使他们能够避免抑制效应通过转磷酸化和激活免疫反应。
The major virulence strategy of phytopathogenic bacteria is to secrete effector proteins into the host cell to target the immune machinery. AvrPto and AvrPtoB are two such effectors from Pseudomonas syringae, which disable an overlapping range of kinases in Arabidopsis and Tomato. Both effectors target surface-localized receptor-kinases to avoid bacterial recognition. In turn, tomato has evolved an intracellular effector-recognition complex composed of the NB-LRR protein Prf and the Pto kinase. Structural analyses have shown that the most important interaction surface for AvrPto and AvrPtoB is the Pto P+1 loop. AvrPto is an inhibitor of Pto kinase activity, but paradoxically, this kinase activity is a prerequisite for defense activation by AvrPto. Here using biochemical approaches we show that disruption of Pto P+1 loop stimulates phosphorylation in trans, which is possible because the Pto/Prf complex is oligomeric. Both P+1 loop disruption and transphosphorylation are necessary for signalling. Thus, effector perturbation of one kinase molecule in the complex activates another. Hence, the Pto/Prf complex is a sophisticated molecular trap for effectors that target protein kinases, an essential aspect of the pathogen's virulence strategy. The data presented here give a clear view of why bacterial virulence and host recognition mechanisms are so often related and how the slowly evolving host is able to keep pace with the faster-evolving pathogen. The bacteria Pseudomonas syringae is a pathogen of many crop species and one of the model pathogens for studying plant and bacterial arms race coevolution. In the current model, plants perceive bacteria pathogens via plasma membrane receptors, and recognition leads to the activation of general defenses. In turn, bacteria inject proteins called effectors into the plant cell to prevent the activation of immune responses. AvrPto and AvrPtoB are two such proteins that inhibit multiple plant kinases. The tomato plant has reacted to these effectors by the evolution of a cytoplasmic resistance complex. This complex is compromised of two proteins, Prf and Pto kinase, and is capable of recognizing the effector proteins. How the Pto kinase is able to avoid inhibition by the effector proteins is currently unknown. Our data shows how the tomato plant utilizes dimerization of resistance proteins to gain advantage over the faster evolving bacterial pathogen. Here we illustrate that oligomerisation of Prf brings into proximity two Pto kinases allowing them to avoid inhibition by the effectors by transphosphorylation and to activate immune responses.
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影响因子：
5.6
作者：
Bonardi V;Dangl JL
通讯作者：
Dangl JL
影响因子：
7.2
作者：
Balmuth, Alexi;Rathjen, John P.
通讯作者：
Rathjen, John P.
DOI：
10.1126/science.1171647
发表时间：
2009-05-08
期刊：
Science (New York, N.Y.)
影响因子：
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通讯作者：
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11.6
作者：
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通讯作者：
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影响因子：
56.9
作者：
Ntoukakis, Vardis;Mucyn, Tatiana S.;Rathjen, John P.
通讯作者：
Rathjen, John P.