Figure 3.

The regulatory role of PI(4,5)P₂ in the salt stress response of plants. PI(4,5)P₂ level is induced by salt stress. PI(4,5)P₂ at the plasma membrane interacts with SYT1 and mediates the salt stress-induced ER and plasma membrane connectivity. The membrane trafficking regulation of PIN2 by PI(4,5)P₂ may participate in salt stress response through the regulation of auxin signaling. PUT3, a polyamine uptake transporter, interacts with SOS1 and SOS2 under salt stress condition, and the application of spermine can induce PI(4,5)P₂ accumulation, which indicate a possible link between polyamine, PI(4,5)P₂ and Na⁺ extrusion under salt stress condition. The hydrolysis of PI(4,5)P₂ by PI-PLC can produce inositol phosphates, which is involved in Ca²⁺ stimulation under salt stress condition, and ABA may participate in this process by the regulation of PLC activity. PI-PLC may also participate in salt stress response by the regulation of proline synthesis and ER stress response, and the further catalysis by DGK can improve plant salt tolerance through PA signaling. PI, phosphatidylinositol; PI(4,5)P₂, PI 4,5-bisphosphate; PM, plasma membrane; SYT1, synaptotagmin 1; PM, plasma membrane; ER, endoplasmic reticulum; ABA, abscisic acid; PI-PLC, phosphatidylinositol-phospholipase C; PIN2, PIN-FORMED 2; DGK, diacylglycerol kinase; PUT3: polyamine uptake transporter 3; SOS, salt overly sensitive.