PROTEIN PHOSPOHATASE 95 Regulates Phosphate Homeostasis by Affecting Phosphate Transporter Trafficking in Rice
PROTEIN PHOSPOHATASE 95 Regulates Phosphate Homeostasis by Affecting Phosphate Transporter Trafficking in Rice
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蛋白质磷酸酶 95 通过影响水稻中磷酸盐转运蛋白的运输来调节磷酸盐稳态
DOI：
10.1105/tpc.19.00685
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发表时间：
--
期刊：
影响因子：
11.6
通讯作者：
Chuanzao Mao
中科院分区：
文献类型：
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作者：
Zhili Yang;Jian Yang;Yan Wang;Fei Wang;Wenxuan Mao;Qiuju He;Jiming Xu;Zhongchang Wu;Chuanzao Mao
植物对磷酸盐（Pi）的吸收依赖于质膜（PM）定位的磷酸盐转运体（PTs）。在水稻（Oryza sativa）中，OsCK2磷酸化PTs并抑制其从内质网（ER）到PM的运输，但PTs是如何去磷酸化的尚不清楚。我们证明了2C型蛋白磷酸酶（PP2C）蛋白磷酸酶OsPP95与OsPT2和OsPT8相互作用，并使OsPT8的Ser-517去磷酸化。过表达gospp95的水稻植株减少了OsPT8的磷酸化，促进了OsPT2和OsPT8从内质网转运到内质网，导致Pi积累。在Pi充足条件下，spp95突变体幼叶的Pi水平低于野生型，而老叶的Pi水平高于野生型，尽管突变体和野生型的茎部整体Pi水平相同。在野生型中，spp95在Pi饥饿条件下积累，但在Pi充足条件下迅速降解。我们发现OsPHO2与OsPP95相互作用并诱导其降解。我们得出结论，OsPP95是一种由OsPHO2负调控的蛋白磷酸酶，通过去磷酸化PTs并影响其转运到PM，积极调节Pi的稳态和再动员，这是适应可变Pi条件所需的可逆过程。
Phosphate (Pi) uptake in plants depends on plasma membrane (PM)-localized phosphate transporters (PTs). OsCK2 phosphorylates PTs and inhibits their trafficking from the endoplasmic reticulum (ER) to the PM in rice (Oryza sativa), but how PTs are dephosphorylated is unknown. We demonstrate that the protein phosphatase type 2C (PP2C) protein phosphatase OsPP95 interacts with OsPT2 and OsPT8 and dephosphorylates OsPT8 at Ser-517. Rice plants overexpressingOsPP95reduced OsPT8 phosphorylation and promoted OsPT2 and OsPT8 trafficking from the ER to the PM, resulting in Pi accumulation. Under Pi-sufficient conditions, Pi levels were lower in young leaves and higher in old leaves inospp95mutants than in those of the wild type, even though the overall shoot Pi levels were the same in the mutant and the wild type. In the wild type, OsPP95 accumulated under Pi starvation but was rapidly degraded under Pi-sufficient conditions. We show that OsPHO2 interacts with and induces the degradation of OsPP95. We conclude that OsPP95, a protein phosphatase negatively regulated by OsPHO2, positively regulates Pi homeostasis and remobilization by dephosphorylating PTs and affecting their trafficking to the PM, a reversible process required for adaptation to variable Pi conditions.