The choline-deficient rat liver has been chosen as a physiologically relevant model system in which to study the regulation of phosphatidylcholine biosynthesis. When 50-g rats were placed on a choline-deficient diet for 3 days, the activity of CTP:phosphocholine cytidylyltransferase (CT) was increased 2-fold in the microsomes and decreased proportionately in the cytosol. A low titer antibody to...

In eukaryotes, many receptor agonists use phospholipase-generated lipids as intracellular messengers. Receptor occupation stimulates the production of polyunsaturated 1,2-diacylglycerols by phosphatidylinositol-4,5-bisphosphate specific phospholipases C and/or of mono-unsaturated and saturated phosphatidates by phospholipase-D-catalysed phosphatidylcholine breakdown. The primary phospholipase p...

Brindley, D. N. & Bowley, M. (1975) Biochem. J. 148,461-469 Fallon,H. J.,Banvick, J.,Lamb,R.G. &vandenBosch,H.(1975)J. LipidRes. 16,107-115 Lamb, R. G. & Fallon, H. J. (1974~) Biochim. Biophys. Actu 348, 166178 Lamb, R. G. & Fallon, H. J. (19746) Biochim. Biophys. Actu 348, 179-188 Lamb. R. G.. Wood, C. K., Guzelian, P. S. & Fallon, H. J. (1976) Fed. Proc. Fed. Am. SOC. Exp. Biol. 35,746 Lamb, ...

Variations in phosphatidate phosphohydrolase (PAP) activity and triacylglycerol concentration were measured in pregnant and hormone-treated non-pregnant female rats. PAP activity in adipose tissue was elevated by 61% during pregnancy. The increase in the enzyme activity was paralleled with a rise in serum triacylglycerol concentration (44%). Estradiol injecting into non-pregnant rats increased ...

Yeast App1p is a phosphatidate phosphatase (PAP) that associates with endocytic proteins at cortical actin patches. App1p, which catalyzes the conversion of phosphatidate (PA) to diacylglycerol, is unique among Mg(2+)-dependent PAP enzymes in that its reaction is not involved with de novo lipid synthesis. Instead, App1p PAP is thought to play a role in endocytosis because its substrate and prod...

The human LPIN1 gene encodes the protein lipin 1, which possesses phosphatidate (PA) phosphatase (3-sn-phosphatidate phosphohydrolase; EC 3.1.3.4) activity (Han, G.-S., Wu, W.-I., and Carman, G. M. (2006) J. Biol. Chem. 281, 9210-9218). In this work, we characterized human lipin 1 alpha, beta, and gamma isoforms that were expressed in Escherichia coli and purified to near homogeneity. PA phosph...

latter were present, the amount of label in the glycerol moiety of the triacylglycerols was increased &fold and that in the diacylglycerol fraction was increased 3-fold. Fatty acids derived from glucose were found mainly in the triacylglycerols, especially in the presence of exogenous free fatty acids, although appreciable amounts of label again accumulated in the diacylglycerols. The finding t...