Garcia-Hernandez Selene, Morello-López Jorge, Haslam Richard, Amorim-Silva Vitor, Moya-Cuevas José, Catalá Rafael, Michaelson Louise, Pérez-Sancho Jessica, Marković Vedrana, Salinas Julio, Napier Johnathan, Jaillais Yvon, Ruiz-Lopez Noemí, Botella Miguel A
Área de Mejora y Fisiología de Plantas. Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Universidad de Málaga-Consejo Superior de Investigaciones Científicas, Málaga 29010, Spain.
Rothamsted Research, Harpenden AL5 2JQ, United Kingdom.
Proc Natl Acad Sci U S A. 2025 Jun 10;122(23):e2421334122. doi: 10.1073/pnas.2421334122. Epub 2025 Jun 2.
A universal response of plants to environmental stresses is the activation of plasma membrane (PM) phospholipase C, which hydrolyzes phosphoinositides to produce soluble inositol phosphate and diacylglycerol (DAG). Because of their conical shape, DAG amounts have to be tightly regulated or they can destabilize membranes. We previously showed that upon stress, Synaptotagmin1 (SYT1) transports DAG from the PM to the endoplasmic reticulum (ER) at ER-PM Contact Sites (CS). Here, we addressed the fate of the incoming DAG in the ER. We show that diacylglycerol kinases (DGKs) DGK1 and DGK2 form a module with SYT1 functionally coupling DAG transport and phosphorylation at ER-PM CS. Although SYT1 and DGK1/DGK2 do not show exclusive ER-PM CS localization, their interaction occurs specifically at ER-PM CS and the removal of ER-PM CS abolishes the interaction. Lipidomic analysis of a double mutant supports that DGK1 and DGK2 phosphorylate DAG at the ER and transcriptomic and phenotypic analyses indicate that SYT1 and DGK1/DGK2 are functionally related. Taken together, our results highlight a mechanism at ER-PM CS that coordinates the transfer of DAG from the PM to the ER by SYT1 upon stress and the concomitant phosphorylation of DAG by DGK1 and DGK2 at the ER. These findings underscore the critical role of spatial coordination in lipid metabolism during stress-induced membrane remodeling.
植物对环境胁迫的一种普遍反应是质膜（PM）磷脂酶C的激活，该酶水解磷酸肌醇以产生可溶性肌醇磷酸和二酰基甘油（DAG）。由于其锥形形状，DAG的量必须受到严格调节，否则它们会破坏膜的稳定性。我们之前表明，在胁迫下，突触结合蛋白1（SYT1）在内质网-质膜接触位点（CS）将DAG从质膜转运到内质网（ER）。在这里，我们研究了内质网中进入的DAG的命运。我们发现二酰基甘油激酶（DGK）DGK1和DGK2与SYT1形成一个模块，在内质网-质膜接触位点功能上偶联DAG转运和磷酸化。虽然SYT1和DGK1/DGK2并不特异性定位于内质网-质膜接触位点，但它们的相互作用专门发生在内质网-质膜接触位点，去除内质网-质膜接触位点会消除这种相互作用。对双突变体的脂质组分析支持DGK1和DGK2在内质网中磷酸化DAG，转录组和表型分析表明SYT1和DGK1/DGK2在功能上相关。综上所述，我们的结果突出了内质网-质膜接触位点的一种机制，该机制在胁迫时协调SYT1将DAG从质膜转运到内质网以及DGK1和DGK2在内质网中对DAG的伴随磷酸化。这些发现强调了应激诱导膜重塑过程中脂质代谢空间协调的关键作用。
