The ability of purified Rous sarcoma virus transforming gene product, pp60v-src, to phosphorylate phosphatidylinositol and diacylglycerol was investigated. Phosphatidylinositol was phosphorylated to form both mono- and diphosphorylated derivatives. 1,2-Diacylglycerol was phosphorylated to form phosphatidic acid. These activities showed the same thermolability and the same sensitivity to inhibit...

Intact mitochondria from the endosperm of castor bean were isolated on linear sucrose gradients. These mitochondria were ruptured and the membranes separated on discontinuous sucrose gradients into outer membrane, intact inner membrane, and ruptured inner membrane fractions. Each membrane fraction was examined for its capacity to synthesize phosphatidylglycerol, CDP-diglyceride, phosphatidylcho...

Stimulation by appropriate agents of protein and polypeptide secretion in various glands is accompanied by an increased turnover of P32 in phospholipides; the effect is greatest in phosphoinositide and phosphatidic acid (l-5). To establish whether the phospholipide effect is confined to protein and polypeptide secretion or whether it may also be concerned with the secretion of smaller molecules...

A technique is described for the radiochemical assay of phosphatidic acid phosphohydrolase activity in rat brain. Radiochemically pure 32P-labeled phosphatidic acid of known specific radioactivity and structure, which was biosynthesized in vitro by the diacylglycerol kinase of E. coli, was used as the substrate. As little as 5 microgram of microsomal or mitochondrial protein can be used for the...

Fluorescent phosphatidic acid and phosphatidylcholine were used to characterize lipid-transport pathways into lipid bodies in an oleaginous fungus, Mortierella ramanniana var. angulispora. Several characteristics of the lipid transport such as temperature dependence and ATP dependence were evaluated. The transport depicted by these fluorescent lipids was consistent with metabolism of radiolabel...

During long-term dietary n-3 fatty acid supplementation, eicosapentaenoic acid (EPA) is not incorporated into phosphatidylinositol or -serine of human platelets in vivo and is not detectable in phosphatidic acid upon stimulation with thrombin. However, EPA is released from platelet phospholipids and metabolized to thromboxane B3 (TXB3). In contrast, in vitro, platelets incorporate [14C]EPA into...

Phosphatidic acid and lysophosphatidic acid are minor but important anionic bioactive lipids involved in a number of key cellular processes, yet these molecules have a simple phosphate headgroup. To find out what is so special about these lipids, we determined the ionization behavior of phosphatidic acid (PA) and lysophosphatidic acid (LPA) in extended (flat) mixed lipid bilayers using magic an...