Phosphorylation of TGB1 by protein kinase CK2 promotes barley stripe mosaic virus movement in monocots and dicots.
Phosphorylation of TGB1 by protein kinase CK2 promotes barley stripe mosaic virus movement in monocots and dicots.
复制标题
蛋白激酶 CK2 磷酸化 TGB1 可促进大麦条纹花叶病毒在单子叶植物和双子叶植物中的运动。
DOI：
10.1093/jxb/erv237
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发表时间：
2015-08
影响因子：
6.9
通讯作者：
Li D
中科院分区：
文献类型：
--
作者：
Hu Y;Li Z;Yuan C;Jin X;Yan L;Zhao X;Zhang Y;Jackson AO;Wang X;Han C;Yu J;Li D
TGB 1蛋白的CK2磷酸化通过影响TGB 1和TGB 3蛋白之间的相互作用在促进大麦条纹花叶病毒在单子叶植物和双子叶植物中的移动中具有关键作用。大麦条纹花叶病毒（BSMV）三重基因块1（TGB 1）蛋白是病毒细胞间运动所必需的。然而，很少有信息是关于这些活动是如何调节的翻译后修饰。在本研究中，我们发现BSMV新疆株TGB 1（XJTGB 1）在体内和体外被来自大麦和烟草的蛋白激酶CK 2磷酸化。液相色谱串联质谱分析和体外磷酸化测定表明，Thr-401是XJTGB 1蛋白的主要磷酸化位点，并表明Thr-395激酶对接位点支持Thr-401磷酸化。用丙氨酸（T395A）取代Thr-395仅中度损害病毒细胞间运动和全身感染。相反，Thr-401丙氨酸（T401A）病毒突变体不能全身感染N. benthamiana，但在单子叶植物宿主中仅具有较小的影响。用天冬氨酸取代Thr-395或Thr-401干扰单子叶植物和双子叶植物细胞间的运动，并且植物未能发展系统性感染。然而，在Thr-395和Thr-401处具有单个谷氨酸取代的病毒衍生物在单子叶植物宿主中产生了几乎正常的系统感染，但不能感染N.双突变体均不能侵染双子叶植物和单子叶植物。突变体XJTGB1T395A/T401A减弱了XJTGB1和XJTGB3蛋白之间的体外相互作用，但对XJTGB1 RNA结合能力影响不大。总而言之，我们的结果支持CK 2磷酸化在单子叶植物和双子叶植物中BSMV运动中的关键作用，并为磷酸化在TGB蛋白功能中的作用提供了新的见解。
CK2 phosphorylation of the TGB1 protein has a critical role in promoting barley stripe mosaic virus movement in monocots and dicots by affecting the interactions between TGB1 and TGB3 proteins. The barley stripe mosaic virus (BSMV) triple gene block 1 (TGB1) protein is required for virus cell-to-cell movement. However, little information is available about how these activities are regulated by post-translational modifications. In this study, we showed that the BSMV Xinjiang strain TGB1 (XJTGB1) is phosphorylated in vivo and in vitro by protein kinase CK2 from barley and Nicotiana benthamiana. Liquid chromatography tandem mass spectrometry analysis and in vitro phosphorylation assays demonstrated that Thr-401 is the major phosphorylation site of the XJTGB1 protein, and suggested that a Thr-395 kinase docking site supports Thr-401 phosphorylation. Substitution of Thr-395 with alanine (T395A) only moderately impaired virus cell-to-cell movement and systemic infection. In contrast, the Thr-401 alanine (T401A) virus mutant was unable to systemically infect N. benthamiana but had only minor effects in monocot hosts. Substitution of Thr-395 or Thr-401 with aspartic acid interfered with monocot and dicot cell-to-cell movement and the plants failed to develop systemic infections. However, virus derivatives with single glutamic acid substitutions at Thr-395 and Thr-401 developed nearly normal systemic infections in the monocot hosts but were unable to infect N. benthamiana systemically, and none of the double mutants was able to infect dicot and monocot hosts. The mutant XJTGB1T395A/T401A weakened in vitro interactions between XJTGB1 and XJTGB3 proteins but had little effect on XJTGB1 RNA-binding ability. Taken together, our results support a critical role of CK2 phosphorylation in the movement of BSMV in monocots and dicots, and provide new insights into the roles of phosphorylation in TGB protein functions.