Diacylglyceryl

Diacylglyceryl, commonly referred to as diacylglycerol (DAG), is a diacyl glycerol moiety found in many lipids. It consists of a glycerol backbone with two fatty acid chains esterified to two of the hydroxyl groups, leaving the remaining hydroxyl accessible for further linkage in certain lipid molecules. The specific fatty acid chains vary in length and degree of saturation across different lipids and species.

DAG is an important intermediate in lipid metabolism and a central signaling lipid in cells. It is produced by hydrolysis of triacylglycerols (TAG) through lipases or by the phospholipase C–mediated cleavage of certain phospholipids, such as phosphatidylinositol 4,5-bisphosphate. In signaling pathways, DAG acts as a second messenger that activates protein kinase C (PKC) isoforms and other DAG-sensitive proteins. DAG can be rapidly metabolized further by diacylglycerol kinases to form phosphatidic acid, another lipid signaling molecule, linking DAG signaling to broader lipid regulatory networks.

Physically, DAG is less polar than many phospholipids and tends to promote non-bilayer membrane structures, which can influence membrane curvature and fusion processes. As a lipid component, DAG serves both as a transient metabolic intermediate and as a functional signaling molecule, with cellular levels tightly regulated by lipid metabolism and signaling pathways. In biochemical contexts, DAG is often studied as a molecule that bridges lipid metabolism and signal transduction, distinct from monoacylglycerol and triacylglycerol species.