1. Arabidopsis heterotrimeric G proteins regulate immunity by directly coupling to the FLS2 receptor.
- Author
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Xiangxiu Liang, Pingtao Ding, Kehui Lian, Jinlong Wang, Miaomiao Ma, Lin Li, Lei Li, Meng Li, Xiaojuan Zhang, She Chen, Yuelin Zhang, and Jian-Min Zhou
- Subjects
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ARABIDOPSIS proteins , *FLAGELLIN , *EPITOPES , *PROTEASOMES , *G proteins - Abstract
The Arabidopsis immune receptor FLS2 perceives bacterial flagellin epitope flg22 to activate defenses through the central cytoplasmic kinase BIK1. The heterotrimeric G proteins composed of the non-canonical Gα protein XLG2, the Gβ protein AGB1, and the Gγ proteins AGG1 and AGG2 are required for FLS2-mediated immune responses through an unknown mechanism. Here we show that in the pre-activation state, XLG2 directly interacts with FLS2 and BIK1, and it functions together with AGB1 and AGG1/2 to attenuate proteasome-mediated degradation of BIK1, allowing optimum immune activation. Following the activation by flg22, XLG2 dissociates from AGB1 and is phosphorylated by BIK1 in the N terminus. The phosphorylated XLG2 enhances the production of reactive oxygen species (ROS) likely by modulating the NADPH oxidase RbohD. The study demonstrates that the G proteins are directly coupled to the FLS2 receptor complex and regulate immune signaling through both pre-activation and post-activation mechanisms. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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