Triacylglycerols are synthesized from fatty acyl CoAs and glycerol 3-phosphate.The   glycolytic   intermediate   dihydroxyacetone phosphate   is   first reduces   to glycerol   3-phosphate   that is, in turn, acylated   by glycerol-3- phosphate acyltransferase to make lysophosphatidic acid. This is then reacted with an additional acyl CoA molecule to form phosphatidic acid.  Removal of the phosphate set from phosphatidic   acid makes diacylglycerol (DAG) that is additional acylated with a third acyl CoA molecule to type triacylglycerol. ATP is not included in the biosynthesis of triacylglycerols.  Alternatively the reactions are driven by the cleavage of the high-energy thioester bond between the acyl moiety and CoA. Both phosphatidic acid (phosphatidate) and DAG is also used as a second messenger in cell signaling and DAG is also used in the synthesis of membrane phospholipids.