Phosphatidic acid: from biophysical properties to diverse functions.

Phosphatidic acid (PA), the simplest phospholipid, acts as a key metabolic intermediate and second messenger that impacts diverse cellular and physiological processes across species ranging from microbes to plants and mammals. The cellular levels of PA dynamically change in response to stimuli, and multiple enzymatic reactions can mediate its production and degradation. PA acts as a signaling molecule and regulates various cellular processes via its effects on membrane tethering, enzymatic activities of target proteins, and vesicular trafficking. Due to its unique physicochemical properties compared with other phospholipids, PA has emerged as a class of new lipid mediators influencing membrane structure, dynamics, protein interactions. This review will summarize the biosynthesis, dynamics, and cellular functions and properties of PA.