Department of Botany, University of Delhi, Delhi, 110007, India.
Translational Health Science and Technology Institute, Faridabad, Haryana, 121001, India.
Plant Physiol Biochem. 2022 Aug 15;185:344-355. doi: 10.1016/j.plaphy.2022.06.018. Epub 2022 Jun 16.
Phosphatidic acid (PA) has emerged as an important lipid signal during abiotic and biotic stress conditions such as drought, salinity, freezing, nutrient starvation, wounding and microbial elicitation. PA acts during stress responses primarily via binding and translocating target proteins or through modulating their activity. Owing to the importance of PA during stress signaling and developmental stages, it is imperative to identify PA interacting proteins and decipher their specific roles. In the present study, we have identified PA binding proteins from the leaves of Arabidopsis thaliana. Mass spectroscopy analysis led to the identification of 21 PA binding proteins with known roles in various cellular processes. One of the PA-binding proteins identified during this study, AtARGAH2, was further studied to unravel the role of PA interaction. Recombinant AtARGAH2 binding with immobilized PA on a solid support validated PA-AtARGAH2 binding invitro. PA binding to AtARGAH2 leads to the enhancement of arginase enzymatic activity in a dose dependent manner. Enzyme kinetics of recombinant AtARGAH2 demonstrated a lower K value in presence of PA, suggesting role of PA in efficient enzyme-substrate binding. This simple approach could systematically be applied to perform an inclusive study on lipid binding proteins to elucidate their role in physiology of plants.
磷脂酸（PA）在非生物和生物胁迫条件下（如干旱、盐度、冰冻、营养饥饿、创伤和微生物诱导）已成为一种重要的脂质信号。PA 在胁迫反应中主要通过结合和转运靶蛋白或通过调节其活性来发挥作用。由于 PA 在胁迫信号转导和发育阶段的重要性，因此识别 PA 相互作用蛋白并阐明其特定作用至关重要。在本研究中，我们从拟南芥叶片中鉴定了 PA 结合蛋白。质谱分析鉴定出 21 种 PA 结合蛋白，它们在各种细胞过程中具有已知的作用。在这项研究中鉴定出的一种 PA 结合蛋白 AtARGAH2 进一步研究了 PA 相互作用的作用。重组 AtARGAH2 与固定在固体载体上的 PA 结合，在体外验证了 PA-AtARGAH2 结合。PA 与 AtARGAH2 的结合以剂量依赖的方式增强了精氨酸酶的酶活性。重组 AtARGAH2 的酶动力学研究表明，在存在 PA 的情况下，K 值较低，表明 PA 在有效酶-底物结合中起作用。这种简单的方法可以系统地应用于进行脂质结合蛋白的综合研究，以阐明它们在植物生理学中的作用。
