biostudies-literatureLi JNatural Science Foundation of Shandong ProvinceNational Natural Science Foundation of Chinae112401https://www.ebi.ac.uk/biostudies/studies/S-EPMC10106984biostudies-literatureUnknown42(8)The maintenance of sodium/potassium (Na⁺ /K⁺ ) homeostasis in plant cells is essential for salt tolerance. Plants export excess Na⁺ out of cells mainly through the Salt Overly Sensitive (SOS) pathway, activated by a calcium signal; however, it is unknown whether other signals regulate the SOS pathway and how K⁺ uptake is regulated under salt stress. Phosphatidic acid (PA) is emerging as a lipid signaling molecule that modulates cellular processes in development and the response to stimuli. Here, we show that PA binds to the residue Lys57 in SOS2, a core member of the SOS pathway, under salt stress, promoting the activity and plasma membrane localization of SOS2, which activates the Na⁺ /H⁺ antiporter SOS1 to promote the Na<sThe EMBO journalPhosphatidic acid-regulated SOS2 controls sodium and potassium homeostasis in Arabidopsis under salt stress.PMC101069843217195632100234ZR2020MC021322702683200021931921001Shen LFan WJin WLi JGuo YHe GHan XZhang WLi YYang YZhang ZWang YYang SfalsePhosphatidic acid-regulated SOS2 controls sodium and potassium homeostasis in Arabidopsis under salt stress.The maintenance of sodium/potassium (Na⁺ /K⁺ ) homeostasis in plant cells is essential for salt tolerance. Plants export excess Na⁺ out of cells mainly through the Salt Overly Sensitive (SOS) pathway, activated by a calcium signal; however, it is unknown whether other signals regulate the SOS pathway and how K⁺ uptake is regulated under salt stress. Phosphatidic acid (PA) is emerging as a lipid signaling molecule that modulates cellular processes in development and the response to stimuli. Here, we show that PA binds to the residue Lys57 in SOS2, a core member of the SOS pathway, under salt stress, promoting the activity and plasma membrane localization of SOS2, which activates the Na⁺ /H⁺ antiporter SOS1 to promote the Na<s2023-01-01T00:00:00Z2023 Apr2026-07-14T16:26:43.989Z2025-04-05T00:30:10.922ZS-EPMC101069843681114510.15252/embj.2022112401