The dynamic changes in membrane phospholipids affect membrane biophysical properties and cell signaling, thereby influencing numerous biological processes. Nonspecific phospholipase C (NPC) enzymes hydrolyze common phospholipids to release diacylglycerol (DAG), which is converted to phosphatidic acid (PA) and other lipids. In this study, two Arabidopsis (Arabidopsis thaliana) tandemly arrayed genes, NPC3 and NPC4, were identified as critical factors modulating auxin-controlled plant growth and tropic responses. Moreover, NPC3 and NPC4 were shown to interact with the auxin efflux transporter PIN-FORMED2 (PIN2). The loss of NPC3 and NPC4 enhanced the endocytosis and vacuolar degradation of PIN2, which disrupted auxin gradients and slowed gravitropic and halotropic responses. Furthermore, auxin-triggered activation of NPC3 and NPC4 is required for the asymmetric PA distribution that controls PIN2 trafficking dynamics and auxin-dependent tropic responses. Collectively, our study reveals an NPC-derived PA signaling pathway in Arabidopsis auxin fluxes that is essential for fine-tuning the balance between root growth and environmental responses.

中文翻译：

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非特异性磷脂酶 C3 和 C4 与 PIN-FORMED2 相互作用调节拟南芥的生长和热带反应

膜磷脂的动态变化影响膜生物物理特性和细胞信号传导，从而影响许多生物过程。非特异性磷脂酶 C (NPC) 酶水解常见的磷脂，释放二酰基甘油 (DAG)，后者转化为磷脂酸 (PA) 和其他脂质。在这项研究中，两个拟南芥（Arabidopsis thaliana）串联排列的基因NPC3和NPC4被确定为调节生长素控制的植物生长和热带反应的关键因子。此外，NPC3 和 NPC4 与生长素外排转运蛋白 PIN-FORMED2 (PIN2) 相互作用。NPC3 和 NPC4 的缺失增强了 PIN2 的内吞作用和液泡降解，从而破坏了生长素梯度并减慢了向重力和嗜盐反应。此外，生长素触发的 NPC3 和 NPC4 激活对于控制 PIN2 运输动态和生长素依赖性热带反应的不对称 PA 分布是必需的。总的来说，我们的研究揭示了拟南芥生长素通量中 NPC 衍生的 PA 信号通路，这对于微调根生长和环境响应之间的平衡至关重要。