Phospholipase C activity in palate mesenchyme cells: calcium and pH requirements, substrate specificity, and subcellular localization.
Primary cultures of mouse embryo palate mesenchyme cells were incubated with [3H]arachidonic acid and [14C]stearic acid in order to radiolabel their lipids. The cells were then washed, collected by centrifugation, and homogenized. Incubation of the homogenates under various conditions revealed that deoxycholate inhibited phospholipase A activity and stimulated a phospholipase C activity in these cells which preferentially degraded phosphatidylinositol (PI) compared to phosphatidylcholine (PC), -ethanolamine (PE), and -serine (PS). Expression of this phospholipase C (E.C. 3.1.4.10) activity was dependent on Ca2+ and had a pH optimum of no more than 7.0-7.5. Centrifugation of the homogenates at 105,000g for 30 min produced a membranous fraction that contained phospholipase C activity with characteristics similar to those of the enzyme found in the supernatant. Such a dual distribution of this enzyme may reflect that mouse embryo palate mesenchyme cells are neural crest in origin.
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D004622:Embryo, Mammalian / Q000201:enzymology; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D051379:Mice; D008810:Mice, Inbred C57BL; D010159:Palate / Q000201:enzymology*; D010716:Phosphatidylinositols; D013347:Subcellular Fractions / Q000378:metabolism; D013379:Substrate Specificity; D010738:Type C Phospholipases / Q000378:metabolism*
D010716:Phosphatidylinositols; D010738:Type C Phospholipases; D002118:Calcium