[Cellular phospholipases A2, structure-function relationship]

Two PLA2 are involved in cell signaling and in phospholipid homeostasis in mammalian cells. The first one is a 14 kDa protein whose cDNA was cloned in 1989. This enzyme exhibits a strong homology with pancreatic PLA2 but is more related to type II PLA2. This PLA2 is secreted by different tissues in response to inflammatory processes. Their main function seems to be the hydrolysis of membranes of altered cells or of bacteria and the stimulation of lipid mediator synthesis. The first cDNA of an another important PLA2 group was cloned in 1991. The protein deduced is a 88 kDa cytoplasmic protein. It is involved in cell signaling by stimulating the production of free fatty acids and of their oxygenated products. These products might in turn either activate transducing proteins or stimulate membrane receptors.