Fatty acids and cell signal transduction

Fatty acids released from membrane phospholipids by cellular phospholipases or available to the cell from the extracellular environment are important cell signalling molecules. Fatty acids can act as second messengers involved in the transduction of external signals because their concentrations are rapidly and transiently altered in response to the binding of specific agonists to plasma membrane receptors, and they substitute for the classical second messengers of the inositide phospholipid and the cyclic AMP signal transduction pathways. Fatty acids are also modulators because they act in a reversible manner at a precise intracellular location for a very short time to amplify, attenuate or deviate a signal. Fatty acids modify the activities of phospholipases, protein kinases, G-proteins, adenylate and guanylate cyclases as well as ion channels and other biochemical events involved in stimulus-response coupling mechanisms. The action of fatty acids on signal transduction pathways can be direct and/or indirect (by catabolic conversion of arachidonic acid to eicosanoids). However, a number of studies clearly show that fatty acids per se are messenger and modulator molecules mediating responses of the cell to extracellular signals.