Pancreatic-Type Phospholipase A2 Activates Prostaglandin E2 Production in Rat Mesangial Cells by Receptor Binding Reaction

• Published in: Journal of biochemistry (Tokyo) Vol. 117; no. 2; pp. 420 - 424
• Main Authors: Kishino, Junji, Kawamoto, Keiko, Ishizaki, Jun, Verheij, Hubertus M., Ohara, Osamu, Arita, Hitoshi
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.02.1995
• Subjects: Animals; Binding, Competitive; CHO Cells; Cricetinae; Dinoprostone - isolation & purification; Dinoprostone - metabolism; Electrophoresis, Polyacrylamide Gel; Glomerular Mesangium - metabolism; in vitro mutagenesis; Kinetics; Mutagenesis, Site-Directed; Pancreas - enzymology; pancreatic type I phospholipase A; Phospholipases A - biosynthesis; Phospholipases A - isolation & purification; Phospholipases A - metabolism; Phospholipases A2; Point Mutation; prostaglandin; Rats; receptor binding; Receptors, Cell Surface - biosynthesis; Receptors, Cell Surface - isolation & purification; Receptors, Cell Surface - metabolism; Receptors, Phospholipase A2; Recombinant Proteins - metabolism; Swine; Transfection
• ISSN: 0021-924X
• DOI: 10.1093/jb/117.2.420

Our earlier studies have shown that mammalian pancreatic group I phospholipase A2 (PLA2-I) has its specific receptor (PLA2 receptor) on a wide range of mammalian cells and that the receptor-binding capability of PLA2 is a property of this molecule separable from its enzymatic activity. To clarify whether PLA2 activity is required for eliciting a biological response via the receptor or not, we examined the enzymatic activity of PLA2-I/PLA2 receptor complex and the inducibility of prostaglandin (PG) E2 production in rat mesangial cells by mutant PLA2S-I. Using a recombinant soluble PLA2 receptor, we first found that PLA2-I could not hydrolyze a phospholipid substrate when complexed with the receptor. In the next experiment using various mutant porcine PLA2S-I we found that PGE2 production in rat mesangial cells could be induced by a mutant PLA2-I which retained the receptor- binding activity but had almost completely lost its enzymatic activity. These findings indicate that the enzyme action of PLA2-I is not required for a PLA2-I-induced biological response, i.e., the augmentation of PGE2 production in rat mesangial cells.