Angkawijaya Artik Elisa, Nakamura Yuki
Institute of Plant and Microbial Biology, Academia Sinica, 128 sec.2, Academia Rd., Nankang, Taipei 11529, Taiwan.
Institute of Plant and Microbial Biology, Academia Sinica, 128 sec.2, Academia Rd., Nankang, Taipei 11529, Taiwan.
Biochem Biophys Res Commun. 2017 Dec 9;494(1-2):397-401. doi: 10.1016/j.bbrc.2017.09.094. Epub 2017 Sep 20.
Phosphate-starved plants reduce phosphatidylcholine content presumably to provide an internal phosphate source while replacing membrane phospholipids by galactolipids, a process termed membrane lipid remodeling. However, whether the metabolic fate of released phosphocholine is a phosphate source remains elusive because primary phosphocholine phosphatases in vivo are unknown in seed plants. Here, we show that PECP1 and PS2 are the primary phosphocholine phosphatases in Arabidopsis and function redundantly under phosphate starvation. Under phosphate starvation, the double knockout mutant of PECP1 and PS2 showed reduced content of choline but no severe growth phenotype, which suggests that phosphocholine dephosphorylation is not likely a major source of internal phosphate reserve. We identified primary phosphocholine phosphatases, demonstrated their involvement under phosphate starvation, and updated the metabolic map of membrane lipid remodeling.
缺磷植物会降低磷脂酰胆碱的含量，大概是为了提供一个内部磷源，同时用半乳糖脂取代膜磷脂，这一过程称为膜脂重塑。然而，释放的磷酸胆碱的代谢命运是否是一个磷源仍然不清楚，因为种子植物体内的初级磷酸胆碱磷酸酶尚不清楚。在这里，我们表明PECP1和PS2是拟南芥中的初级磷酸胆碱磷酸酶，并且在磷饥饿条件下功能冗余。在磷饥饿条件下，PECP1和PS2的双敲除突变体胆碱含量降低，但没有严重的生长表型，这表明磷酸胆碱去磷酸化不太可能是内部磷储备的主要来源。我们鉴定了初级磷酸胆碱磷酸酶，证明了它们在磷饥饿条件下的作用，并更新了膜脂重塑的代谢图谱。
