PDF(Pubmed)
Abstract：
Regulator of G-protein signaling (RGS) proteins exhibit GTPase-accelerating protein activities to govern G-protein function. In the rice blast fungus Magnaporthe oryzae, there is a family of at least eight RGS and RGS-like proteins (MoRgs1 to MoRgs8), each exhibiting distinct or shared functions in the growth, appressorium formation, and pathogenicity. MoRgs3 recently emerged as one of the crucial regulators that senses intracellular oxidation during appressorium formation. To explore this unique regulatory mechanism of MoRgs3, we identified the nucleoside diphosphate kinase MoNdk1 that interacts with MoRgs3. MoNdk1 phosphorylates MoRgs3 under induced intracellular reactive oxygen species levels, and MoRgs3 phosphorylation is required for appressorium formation and pathogenicity. In addition, we showed that MoRgs3 phosphorylation determines its interaction with MoCrn1, a coronin-like actin-binding protein homolog, which regulates MoRgs3 internalization. Finally, we provided evidence demonstrating that MoRgs3 functions in MoMagA-mediated cAMP signaling to regulate normal appressorium induction. By revealing a novel signal perception mechanism, our studies highlighted the complexity of regulation during the appressorium function and pathogenicity of the blast fungus.
OBJECTIVE: We report that MoRgs3 becomes phosphorylated in an oxidative intracellular environment during the appressorium formation stage. We found that this phosphorylation is carried out by MoNdk1, a nucleoside diphosphate kinase. In addition, this phosphorylation leads to a higher binding affinity between MoRgs3 and MoCrn1, a coronin-like actin-binding protein that was implicated in the endocytic transport of several other RGS proteins of Magnaporthe oryzae. We further found that the internalization of MoRgs3 is indispensable for its GTPase-activating protein function toward the Gα subunit MoMagA. Importantly, we characterized how such cellular regulatory events coincide with cAMP signaling-regulated appressorium formation and pathogenicity in the blast fungus. Our studies uncovered a novel intracellular reactive oxygen species signal-transducing mechanism in a model pathogenic fungus with important basic and applied implications.
OBJECTIVE: We report that MoRgs3 becomes phosphorylated in an oxidative intracellular environment during the appressorium formation stage. We found that this phosphorylation is carried out by MoNdk1, a nucleoside diphosphate kinase. In addition, this phosphorylation leads to a higher binding affinity between MoRgs3 and MoCrn1, a coronin-like actin-binding protein that was implicated in the endocytic transport of several other RGS proteins of Magnaporthe oryzae. We further found that the internalization of MoRgs3 is indispensable for its GTPase-activating protein function toward the Gα subunit MoMagA. Importantly, we characterized how such cellular regulatory events coincide with cAMP signaling-regulated appressorium formation and pathogenicity in the blast fungus. Our studies uncovered a novel intracellular reactive oxygen species signal-transducing mechanism in a model pathogenic fungus with important basic and applied implications.
摘要：
G蛋白信号传导（RGS）蛋白的调节剂表现出GTP酶加速蛋白活性以控制G蛋白功能。在稻瘟病真菌稻瘟病中，有一个家族至少八个RGS和RGS样蛋白（MoRgs1至MoRgs8），每个人在成长中都表现出不同或共同的功能，附睾形成，和致病性。最近出现的MoRgs3是在附着层形成过程中感知细胞内氧化的关键调节因子之一。为了探索MoRgs3的这种独特调节机制，我们鉴定了与MoRgs3相互作用的核苷二磷酸激酶MoNdk1。MoNdk1在诱导的细胞内活性氧水平下磷酸化MoRgs3，和MoRgs3磷酸化是形成和致病性所必需的。此外,我们表明，MoRgs3磷酸化决定了它与MoCrn1的相互作用，MoCrn1是一种类似于冠状肌动蛋白结合蛋白的同源物，它调节MoRgs3的内化。最后,我们提供的证据表明MoRgs3在MoMagA介导的cAMP信号传导中起作用，以调节正常的贴壁诱导。通过揭示一种新的信号感知机制，我们的研究强调了稻瘟病菌在附睾功能和致病性过程中调节的复杂性。
目的：我们报道了MoRgs3在细胞内的氧化环境中在贴壁形成阶段发生磷酸化。我们发现这种磷酸化是由核苷二磷酸激酶MoNdk1进行的。此外,这种磷酸化导致MoRgs3和MoCrn1之间更高的结合亲和力,MoCrn1是一种冠状肌动蛋白结合蛋白,与稻瘟病的其他几种RGS蛋白的内吞转运有关.我们进一步发现，MoRgs3的内化对于其GTP酶激活蛋白对Gα亚基MoMagA的功能是必不可少的。重要的是,我们表征了这些细胞调节事件如何与cAMP信号调节的结合菌的形成和致病性一致。我们的研究揭示了模型病原真菌中一种新颖的细胞内活性氧信号转导机制，具有重要的基础和应用意义。
目的：我们报道了MoRgs3在细胞内的氧化环境中在贴壁形成阶段发生磷酸化。我们发现这种磷酸化是由核苷二磷酸激酶MoNdk1进行的。此外,这种磷酸化导致MoRgs3和MoCrn1之间更高的结合亲和力,MoCrn1是一种冠状肌动蛋白结合蛋白,与稻瘟病的其他几种RGS蛋白的内吞转运有关.我们进一步发现，MoRgs3的内化对于其GTP酶激活蛋白对Gα亚基MoMagA的功能是必不可少的。重要的是,我们表征了这些细胞调节事件如何与cAMP信号调节的结合菌的形成和致病性一致。我们的研究揭示了模型病原真菌中一种新颖的细胞内活性氧信号转导机制，具有重要的基础和应用意义。
