Phospholipase C activity in palate mesenchyme cells: calcium and pH requirements, substrate specificity, and subcellular localization
Chepenik, K.P.; George-Weinstein, M.; Caamano-Haigh, R.
Journal of Craniofacial Genetics and Developmental Biology 6(4): 383-392
1986
ISSN/ISBN: 0270-4145 PMID: 3793862 Document Number: 276360
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 (1) inhibited phospholipase A activity and (2) 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 105,000 g 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.