Résumé
Phosphoinositides are signaling lipids that regulate cellular responses by acting as gatekeepers of organelle identity or modulating protein localization and activity.1 They are well established core elements of classical receptor kinase signaling in animals.2 However, in8 plants, rapid phosphoinositide remodeling has not yet been recognized as a key regulation of receptor-like kinase signaling.3,4 Here, we show that the receptor-like kinase FERONIA (FER) triggers acute phosphoinositide remodeling in response to Rapid ALkalinisation Factors23 (RALF23) and RALF1 peptides. Using high-resolution confocal microscopy, combined with microfluidics and advanced image analysis, we reveal that RALF peptides induce a rapid and FER-dependent recruitment of phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2) sensors at the plasma membrane and a concomitant decrease of phosphatidylinositol-4-phosphate (PI4P) sensors from the cell surface. This PI4P-to-PI(4,5)P2 conversion is regulated by PI4P 5-Kinase7 (PIP5K7), PIP5K8 and PIP5K9 and is required for RALF-induced endocytosis, a response known to safeguard growth upon recovery from stress episodes.5–7 These findings highlight a mechanism where FER regulates the PI4P/PI(4,5)P2 balance through PIP5Ks to control stress-induced endocytosis, linking phosphoinositide dynamics, vesicular trafficking and plant growth adaptation. In addition, it uncovers that peptide/receptor modules have co-opted acute phosphoinositide conversion to act as lipid second messengers in both plant and animal systems.