title: Phosphatidic acid (PA) binds PP2AA1 to regulate PP2A activity and PIN1 polar localization.
abstract: Phospholipase D (PLD) exerts broad biological functions in eukaryotes through regulating downstream effectors by its product, phosphatidic acid (PA). Protein kinases and phosphatases, such as mammalian target of rapamycin (mTOR), Protein Phosphatase 1 (PP1) and Protein Phosphatase 2C (PP2C), are PA-binding proteins that execute crucial regulatory functions in both animals and plants. PA participates in many signaling pathways by modulating the enzymatic activity and/or subcellular localization of bound proteins. In this study, we demonstrated that PLD-derived PA interacts with the scaffolding A1 subunit of Protein Phosphatase 2A (PP2A) and regulates PP2A-mediated PIN1 dephosphorylation in Arabidopsis. Genetic and pharmacological studies showed that both PA and PP2A participate in the regulation of auxin distribution. In addition, both the phosphorylation status and polar localization of PIN1 protein were affected by PLD inhibitors. Exogenous PA triggered the membrane accumulation of PP2AA1 and enhanced the PP2A activity at membrane, while PLD inhibition resulted in the reduced endosomal localization and perinuclear aggregation of PP2AA1. These results demonstrate the important role of PLD-derived PA in normal PP2A-mediated PIN dephosphorylation and reveal a novel mechanism, in which PA recruits PP2AA1 to the membrane system and regulates PP2A function on membrane-targeted proteins. As PA and PP2A are conserved among eukaryotes, other organisms might use similar mechanisms to mediate multiple biological processes.
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese academy of Sciences, 200032 Shanghai, People's Republic of China.
authors.forename: Hong-Bo
authors.initials: HB
authors.lastname: Gao
authors.forename: Yu-Jia
authors.initials: YJ
authors.lastname: Chu
authors.forename: Hong-Wei
authors.initials: HW
authors.lastname: Xue
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007210:Indoleacetic Acids / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000378:metabolism*; D018519:Meristem / Q000187:drug effects / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D010712:Phosphatidic Acids / Q000378:metabolism* / Q000494:pharmacology; D010739:Phospholipase D / Q000037:antagonists & inhibitors / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D054648:Protein Phosphatase 2 / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects; D013347:Subcellular Fractions / Q000187:drug effects / Q000201:enzymology
chemical_list: D029681:Arabidopsis Proteins; D004791:Enzyme Inhibitors; D007210:Indoleacetic Acids; D026901:Membrane Transport Proteins; C116363:PIN1 protein, Arabidopsis; D010712:Phosphatidic Acids; C587317:PP2AA1 protein, Arabidopsis; D054648:Protein Phosphatase 2; D010739:Phospholipase D
keywords: PIN1 phosphorylation; PP2A; phosphatidic acid (PA); polar localization.