Abstract
Lipid mediators represent a variety of bioactive substances which are derived from phospholipids. It is considered that these molecules are biofactors in a broad sense. N-Acylethanolamines are ethanolamides of long-chain fatty acids and function as the lipid mediators by exerting various biological actions such as anti-inflammation and appetite suppression. On the other hand, lysophosphatidic acids (LPAs) are wellknown lipid mediators, which have diverse physiological activities including cell proliferation, smooth muscle contraction, and platelet coagulation. Recent analyses have identified several candidate enzymes responsible for the biosynthesis of N-acylethanolamines in mammals. They include three members of the glycerophosphodiesterase (GDE) family (GDE1, GDE4, and GDE7). These proteins catalyze phospholipidhydrolyzing reactions including lysophospholipase D-type hydrolysis to generate N-acylethanolamines as well as LPAs. The enzyme activities of GDE1 and GDE4 are enhanced by Mg2+, while the enzyme activity of GDE7 is increased in a Ca2+-dependent manner, raising a possibility that GDE7 is stimulated through the signal transduction leading to an increase in the intracellular Ca2+ concentration. In this minireview, we we will first introduce the biological activities and metabolism of N-acylethanolamines, and then focus on the catalytic properties of GDE proteins.
