A deazaadenosine-insensitive methylation of phosphatidylethanolamine is involved in lipoprotein secretion.
We have examined the effect of inhibitors of methylation of phosphatidylethanolamine on lipoprotein secretion from cultured rat hepatocytes. The incorporation of [1-3H]ethanolamine into phosphatidylcholine of hepatocytes and secreted lipoproteins was inhibited by greater than 90% by the methylation inhibitors 3-deazaadenosine and Neplanocin. In addition, these compounds strongly inhibited the incorporation of [3-3H]serine into the choline moiety of phosphatidylcholine of the hepatocytes, but had no effect on incorporation of [3-3H]serine into secreted phosphatidylcholine. The results suggest that a pool of phosphatidylcholine targeted for lipoprotein secretion originates from phosphatidylethanolamine made from serine and this methylation reaction has the unique property of being insensitive to 3-deazaadenosine.
D000818:Animals; D019856:Ethanolamine; D004983:Ethanolamines / Q000378:metabolism; D008074:Lipoproteins / Q000378:metabolism*; D008077:Lipoproteins, LDL / Q000378:metabolism; D008079:Lipoproteins, VLDL / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008745:Methylation; D010713:Phosphatidylcholines / Q000378:metabolism; D010714:Phosphatidylethanolamines / Q000378:metabolism*; D051381:Rats; D012263:Ribonucleosides / Q000494:pharmacology*; D012694:Serine / Q000378:metabolism; D014372:Tubercidin / Q000494:pharmacology*
D004983:Ethanolamines; D008074:Lipoproteins; D008077:Lipoproteins, LDL; D008079:Lipoproteins, VLDL; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D012263:Ribonucleosides; C018258:3-deazaadenosine; D012694:Serine; D019856:Ethanolamine; D014372:Tubercidin