Phosphatidylinositol 3-phosphate-binding protein AtPH1 controls the localization of the metal transporter NRAMP1 in Arabidopsis
Phosphatidylinositol 3-phosphate-binding protein AtPH1 controls the localization of the metal transporter NRAMP1 in Arabidopsis
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DOI：
10.1073/pnas.1702975114
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发表时间：
2017-04-18
影响因子：
11.1
通讯作者：
Merlot, Sylvain
中科院分区：
文献类型：
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作者：
Agorio, Astrid;Giraudat, Jerome;Merlot, Sylvain
“过犹不及”完美地描述了生物体在金属方面所面临的困境。细胞内金属稳态的严格控制取决于金属转运蛋白在不同区室膜之间的运输。然而，调节转运蛋白位置的机制在很大程度上仍然未知。发育中的拟南芥幼苗需要天然抗性相关巨噬细胞蛋白（NRAMP3和NRAMP4）转运蛋白从种子液泡储存中重新动员铁，从而获得光合能力。在此，我们报道含普列克底物蛋白同源结构域（PH）的蛋白AtPH1的突变挽救了nramp3 nramp4的缺铁表型。我们的结果表明，AtPH1在体内结合磷脂酰肌醇 - 3 - 磷酸（PI3P）并作用于晚期内体区室。我们进一步表明，AtPH1功能缺失导致金属摄取转运蛋白NRAMP1错误定位到液泡，为nramp3 nramp4表型的逆转提供了理论依据。这项工作确定了一种PH结构域蛋白作为植物金属转运蛋白定位的调节因子，提供了证据表明PH结构域蛋白可能是PI3P用于蛋白质分选的效应物。
"Too much of a good thing" perfectly describes the dilemma that living organisms face with metals. The tight control of metal homeostasis in cells depends on the trafficking of metal transporters between membranes of different compartments. However, the mechanisms regulating the location of transport proteins are still largely unknown. Developing Arabidopsis thaliana seedlings require the natural resistance-associated macrophage proteins (NRAMP3 and NRAMP4) transporters to remobilize iron from seed vacuolar stores and thereby acquire photosynthetic competence. Here, we report that mutations in the pleckstrin homology (PH) domain-containing protein AtPH1 rescue the iron-deficient phenotype of nramp3nramp4. Our results indicate that AtPH1 binds phosphatidylinositol 3-phosphate (PI3P) in vivo and acts in the late endosome compartment. We further show that loss of AtPH1 function leads to the mislocalization of the metal uptake transporter NRAMP1 to the vacuole, providing a rationale for the reversion of nramp3nramp4 phenotypes. This work identifies a PH domain protein as a regulator of plant metal transporter localization, providing evidence that PH domain proteins may be effectors of PI3P for protein sorting.