Lyso-PC is the ubiquitous lipid species generated following PLA2 hydrolysis of phosphatidylcholine. The hydrolysis of phospholipids by arachidonyl-selective PLA2s is the initiating event in many eicosanoid-based signal transduction pathways. Many other reactions also generate phosphatidylcholine species with a free hydroxyl group in the sn-2 position. Lyso-PC augments inflammation through effects on adhesion molecules and growth factors, monocytes, and macrophages. The lymphocyte G protein-coupled receptor G2A binds lyso-PC as a specific ligand with a Kd of 65 nM; this receptor also binds the related phospholipid sphingosyl phosphorylcholine.