Phosphorylation-Dependent Regulation of G-Protein Cycle during Nodule Formation in Soybean
Phosphorylation-Dependent Regulation of G-Protein Cycle during Nodule Formation in Soybean
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DOI：
10.1105/tpc.15.00517
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发表时间：
2015-11-01
期刊：
影响因子：
11.6
通讯作者：
Pandey, Sona
中科院分区：
文献类型：
--
作者：
Choudhury, Swarup Roy;Pandey, Sona
由包含G α、G β和G γ亚基的异源三聚体G蛋白复合物及其调节性RGS（G蛋白信号调节子）蛋白介导的信号传导途径在所有真核生物中是保守的。我们已经表明，特定的Gb和Gg蛋白的大豆（大豆）异源三聚体G蛋白复合物参与调节蛋白质的形成。我们现在证明了结瘤因子受体1（NFR 1）介导的磷酸化在大豆结瘤过程中G蛋白周期调节中的作用。我们还表明，在排卵期间，G-蛋白周期是由RGS蛋白的活性调节。较低或较高的RGS蛋白表达分别导致较少或较多的结节。NFR 1与RGS蛋白相互作用并使其磷酸化。磷酸化RGS蛋白的分析鉴定了特定的氨基酸，当磷酸化时，其导致显著更高的GT3加速活性。这些数据表明在结节发育过程中G蛋白信号的磷酸化调控。我们提出，活性NFR 1受体磷酸化和激活RGS蛋白，这有助于维持Ga蛋白在其非活性，三聚体构象，导致成功的结节发展。或者，RGS蛋白也可能在调节结瘤中起直接作用，因为它们的磷酸模拟物版本的过表达导致在B149突变体中结瘤形成的部分恢复。
Signaling pathways mediated by heterotrimeric G-protein complexes comprising G alpha, G beta, and G gamma subunits and their regulatory RGS (Regulator of G-protein Signaling) protein are conserved in all eukaryotes. We have shown that the specific Gb and Gg proteins of a soybean (Glycine max) heterotrimeric G-protein complex are involved in regulation of nodulation. We now demonstrate the role of Nod factor receptor 1 (NFR1)-mediated phosphorylation in regulation of the G-protein cycle during nodulation in soybean. We also show that during nodulation, the G-protein cycle is regulated by the activity of RGS proteins. Lower or higher expression of RGS proteins results in fewer or more nodules, respectively. NFR1 interacts with RGS proteins and phosphorylates them. Analysis of phosphorylated RGS protein identifies specific amino acids that, when phosphorylated, result in significantly higher GTPase accelerating activity. These data point to phosphorylation-based regulation of G-protein signaling during nodule development. We propose that active NFR1 receptors phosphorylate and activate RGS proteins, which help maintain the Ga proteins in their inactive, trimeric conformation, resulting in successful nodule development. Alternatively, RGS proteins might also have a direct role in regulating nodulation because overexpression of their phospho-mimic version leads to partial restoration of nodule formation in nod49 mutants.