Phosphatidic acid (PA), the smallest and simplest phospholipid is produced from phosphatidylcholine with the help of phospholipase D. This glycerophospholipid is an ester of glycerol, which possess two long-chain fatty acids (LCFAs) at C1 and C2 and phosphoric acid at C3 positions.
Phosphatidic acid (PA) may induce negative curvature in the cytoplasmic leaflet of the plasma membrane, which enables the development of the hemi fusion intermediates, that is essential for the fusion of two membranes.