Phospholipid signaling, lipase

Phospholipids are the major components of the plasma membrane. They are metabolized by phospholipases, which constitute a class of hydrolases that catalyze the hydrolysis of acyl esters and phosphate esters on phospholipids. Phospholipases are classified according to their action on the phospholipid substrate molecule. Phospholipase A2 triggers the production of lipid mediators and remodels the membrane phospholipids. Phospholipase C hydrolyzes the plasma membrane phosphatidylinositol 4,5-bisphosphates and generates diacylglycerol and inositol 1,4,5-trisphosphate, leading to the activation of protein kinase C and elevation of cytosolic Ca2+ levels. Phospholipase D generates phosphatidic acid, which leads to the negative curvature of the plasma membrane. This chapter mainly focuses on the phospholipase-mediated phospholipid metabolism process in the plasma membranes of mammalian cells.