PP2A activates brassinosteroid-responsive gene expression and plant growth by dephosphorylating BZR1.
PP2A activates brassinosteroid-responsive gene expression and plant growth by dephosphorylating BZR1.
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PP2A 通过 BZR1 去磷酸化激活油菜素类固醇响应基因表达和植物生长
DOI：
10.1038/ncb2151
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发表时间：
2011-02
影响因子：
21.3
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中科院分区：
文献类型：
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当油菜素内酯水平低时，gsk3样激酶BIN2磷酸化并使BZR1转录因子失活，从而抑制植物的生长。油菜素内酯通过诱导BZR1的去磷酸化来促进生长，但使BZR1去磷酸化的磷酸酶尚不清楚。通过串联亲和纯化，我们鉴定出蛋白磷酸酶2A （PP2A）是与bzr1相互作用的蛋白。遗传分析表明PP2A在油菜素内酯信号传导和BZR1去磷酸化中起积极作用。PP2A的B '调控亚基成员直接与BZR1假定的含有BZR1 -1突变位点的PEST结构域相互作用。与PP2A的相互作用和PP2A的去磷酸化通过bzr1- 1d突变增强，通过两个intrenicbzr1 - 1dsuppressor突变减弱，并通过删除PEST结构域而消除。本研究揭示了PP2A在去磷酸化和激活BZR1中的关键功能，并完成了从细胞表面受体激酶到细胞核基因调控的油菜素类固醇信号级联的核心组件。
When brassinosteroid levels are low, the GSK3-like kinase BIN2 phosphorylates and inactivates the BZR1 transcription factor to inhibit growth in plants. Brassinosteroid promotes growth by inducing dephosphorylation of BZR1, but the phosphatase that dephosphorylates BZR1 has remained unknown. Here, using tandem affinity purification, we identified protein phosphatase 2A (PP2A) as a BZR1-interacting protein. Genetic analyses demonstrated a positive role for PP2A in brassinosteroid signalling and BZR1 dephosphorylation. Members of the B’ regulatory subunits of PP2A directly interact with BZR1’s putative PEST domain containing the site of thebzr1-1Dmutation. Interaction with and dephosphorylation by PP2A are enhanced by thebzr1-1Dmutation, reduced by two intragenicbzr1-1Dsuppressor mutations, and abolished by deletion of the PEST domain. This study reveals a crucial function for PP2A in dephosphorylating and activating BZR1 and completes the set of core components of the brassinosteroid-signalling cascade from cell surface receptor kinase to gene regulation in the nucleus.