Plant hormones (Literature sources on phytohormones and plant signalling)

Authors: Yoko Ito, Nicolas Esnay, Matthieu Pierre Platre, Valérie Wattelet-Boyer, Lise C. Noack, Louise Fougère, Wilhelm Menzel, Stéphane Claverol, Laetitia Fouillen, Patrick Moreau, Yvon Jaillais and Yohann Boutté.

Nature Communications (2021)

Editor's view: Lipid composition impacts the function of cellular membranes. Here the authors show that a reduction in sphingolipid acyl-chain length promotes phosphoinositide consumption by phospholipase C at the Arabidopsis trans-Golgi network which in turn regulates sorting of the auxin efflux carrier PIN2.

Abstract: "The lipid composition of organelles acts as a landmark to define membrane identity and specify subcellular function. Phosphoinositides are anionic lipids acting in protein sorting and trafficking at the trans-Golgi network (TGN). In animal cells, sphingolipids control the turnover of phosphoinositides through lipid exchange mechanisms at endoplasmic reticulum/TGN contact sites. In this study, we discover a mechanism for how sphingolipids mediate phosphoinositide homeostasis at the TGN in plant cells. Using multiple approaches, we show that a reduction of the acyl-chain length of sphingolipids results in an increased level of phosphatidylinositol-4-phosphate (PtdIns(4)P or PI4P) at the TGN but not of other lipids usually coupled to PI4P during exchange mechanisms. We show that sphingolipids mediate Phospholipase C (PLC)-driven consumption of PI4P at the TGN rather than local PI4P synthesis and that this mechanism is involved in the polar sorting of the auxin efflux carrier PIN2 at the TGN. Together, our data identify a mode of action of sphingolipids in lipid interplay at the TGN during protein sorting."