Disease relevance of Pemt

• Rat hepatoma cells transfected with phosphatidylethanolamine N-methyltransferase secrete more homocysteine than wild-type cells [1].
• Thus, phosphatidylethanolamine N-methyltransferase is an important source of plasma homocysteine and a potential therapeutic target for hyperhomocysteinemia [1].
• Expression of phosphatidylethanolamine N-methyltransferase in Yoshida ascites hepatoma cells and the livers of host rats [2].
• Inactivation of phosphatidylethanolamine N-methyltransferase-2 in aflatoxin-induced liver cancer and partial reversion of the neoplastic phenotype by PEMT transfection of hepatoma cells [3].

High impact information on Pemt

• Rat brain synaptosomes contain an enzyme, phosphatidylethanolamine N-methyltransferase (EC 2.1.1.17), that catalyzes the methylation of phosphatidylethanolamine to form its mono-, di-, and trimethyl (phosphatidylcholine) derivatives [4].
• We show that mice that lack phosphatidylethanolamine N-methyltransferase have plasma levels of homocysteine that are approximately 50% of those in wild-type mice [1].
• We screened the major tissues for the activities of two important enzymes involved in the biosynthesis of phosphatidylcholine, CTP:phosphocholine cytidylyltransferase (CT) and phosphatidylethanolamine N-methyltransferase (PEMT) [5].
• The labeling of phosphatidylcholine in isolated hepatocytes from CD rats was consistent with the conversion of PE to PC being increased as a result of a higher expression of liver PEMT [5].
• Phosphatidylethanolamine levels and regulation of phosphatidylethanolamine N-methyltransferase [6].

Biological context of Pemt

• A potential source for homocysteine is methylation of the lipid phosphatidylethanolamine to phosphatidylcholine by phosphatidylethanolamine N-methyltransferase in the liver [1].
• The appearance of apoptosis in the host liver was associated with a marked reduction in both CT activity and expression as well as an enhancement of PEMT activity and PEMT2 expression [2].
• We investigate whether PEMT controlled cell death and cell proliferation triggered by fasting/refeeding and whether it is a marker of early preneoplastic lesions [7].
• Regulation of rat liver phosphatidylethanolamine N-methyltransferase by cytosolic factors. Examination of a role for reversible protein phosphorylation [8].
• Since both of these activities are influenced by phospholipid methylation, effects of adriamycin on the three catalytic sites of SL phosphatidylethanolamine N-methyltransferase were examined [9].

Anatomical context of Pemt

• However, PEMT activity is negligible in two hepatoma cell lines [10].
• The present study was designed to test the hypothesis that diet- and diabetes-associated changes in enterocyte microsomal membrane phospholipids are due to variations in the activity of two phospholipid metabolizing enzymes, 1,2-diacylglycerol:CDPcholine cholinephosphotransferase (CPT) and phosphatidylethanolamine methyltransferase (PEMT) [11].
• The aim of this study was to evaluate the effect of chronic ethanol ingestion on PEMT activity in the jejunal brush-border membrane (BBM) of adequately nourished rats [12].
• The effect of reagents that modify sulfur-containing amino acid residues in the phosphatidylethanolamine N-methyltransferase was studied in the isolated rat cardiac sarcolemma by employing S-adenosyl-L-[methyl-3H]methionine as a methyl donor [13].
• To elucidate the molecular mechanism underlying the adverse depression of myocardial contractility observed during antiarrhythmic therapy of quinidine, we investigated its action on the phosphatidylethanolamine N-methyltransferase (EC 2.1.1.17) activities of cardiac subcellular membranes [14].

Associations of Pemt with chemical compounds

• Betaine supplementation corrected the ethanol-induced decrease in hepatic SAM:SAH ratios and by normalizing PC production via the PEMT-mediated pathway, significantly reduced fatty infiltration associated with ethanol consumption [15].
• Therefore, we sought to determine whether the protective effect of betaine is via its effect on PEMT activity [15].
• BACKGROUND/AIMS: Previous studies in our laboratory implicated ethanol-induced decreases in hepatocellular S-adenosylmethionine to S-adenosylhomocysteine (SAM:SAH) ratios in lowering the activity of phosphatidylethanolamine methyltransferase (PEMT), which is associated with the generation of steatosis [15].
• PEMT activity decreased, the levels of PEMT2 mRNA decreased and there was an increase in the activity of CTP:phosphocholine cytidylyltransferase, a key regulatory enzyme in the CDP-choline pathway of phosphatidylcholine biosynthesis [10].
• A maximal decrease in PEMT activity (60%) and loss of PEMT2 protein (95%) coincided with maximal DNA synthesis and maximal cytidine triphosphate:phosphocholine cytidylyltransferase activity 36 h and 48 h after lead nitrate stimulation in male and female livers respectively [16].

Other interactions of Pemt

• This preparation contained activities for CTP:phosphocholine cytidylyltransferase, CDP-choline:1,2-diacylglycerol cholinephosphotransferase, CDP-ethanolamine:1,2-diacylglycerol ethanolamine-phosphotransferase, phosphatidylethanolamine-N-methyltransferase, and phosphatidylserine synthase [17].
• The activity of phosphatidylethanolamine N-methyltransferase (PeMT), an enzymic system that catalyses the synthesis of phosphatidylcholine (PtdCho) via sequential methylation of phosphatidylethanolamine (PtdEtn) using S-adenosylmethionine (AdoMet) as a methyl donor, was examined in brain homogenates from rats of various ages [18].

Analytical, diagnostic and therapeutic context of Pemt

• Expression of the enzyme was confirmed by assay of PEMT activity and immunoblotting [19].
• Southern blot analyses of restriction fragments of DNA showed no changes in the PEMT gene in hepatocarcinoma compared with normal liver [10].
• After DENA administration, PEMT protein, evaluated by Western blotting, slightly increased, but it remained below control levels [7].
• Maximal decrease of total PEMT activity (45%) and loss of PEMT2 protein (90%) coincided with maximal DNA synthesis and CTP:phosphocholine cytidylyltransferase activity 24 h after partial hepatectomy in both male and female rats [20].

References