Phosphatidic Acid (PA) has aroused people’s interests due to its role in diverse key biological functions, including its being an intermediate in the synthesis of all membrane glycerophospholipids, a participant of membrane biogenesis, a necessary signaling molecule in cell proliferation and cytoskeletal rearrangement, as well as a participant in endocrine, neuroendocrine exocytosis and synaptic neurotransmission. Mammals can have more than 40 PA subspecies with different fatty acyl chain composition. The understanding of PA in cellular function and human pathology is growing, so it is necessary to give an insight into the precise effects PA subspecies have.
The research team explored the effects and relevance of PA subspecies using the requirement for PA in calcium-regulated exocytosis in the process, and Genetic alteration of phospholipase D (PLD1) was used to analyze the role of PA in successive stage in the exocytotic process within chromaffin cells. It was proven through the experiment that PLD1 promotes the synthesis of different PA species at the plasma membrane granule docking sites. In addition, mono- and di-unsaturated PA can regulate the docking of secretory granules so that the number of secretory events can be regulated. Also, they observed the Onega-3-polyunsaturated PA to regulate fusion pore dynamics as well as the type and amount of molecule releases of each vesicle. Observing using electron-microscopy, researchers found that PA exists in both the cytosolic leaflet of the plasma membrane in stimulated chromaffin cells and the outer leaflet of the docked secretory granules which indicates that PA formed in the plasma membrane can probably spread through lipid mixing to the granule membrane at the docking sites. The study could certainly help people know more about the effects that PA have on human health.