title: Incorporation of serine into the phospholipids of phosphatidylethanolamine-depleted Tetrahymena.
abstract: Phosphatidylserine formation and decarboxylation are decreased in Tetrahymena in which phosphatidylethanolamine has been replaced by its isosteric analog 3-aminopropylphosphonolipid (1,2-diacylglyceryl-3-O-(3-aminopropylphosphonate). The combined activity of the phosphatidylethanolamine: serine phosphatidyltransferase/ phosphatidylserine decarboxylase complex in isolated mitochondria from lipid-altered cells [J. D. Smith and D. A. Giegel (1981) Arch. Biochem, Biophys. 206, 420-423] is about 20% of the activity in mitochondria from control cells. The enzyme activity in the lipid-altered mitochondria is stimulated by the addition of exogenous phosphatidylethanolamine to the assay system while the enzymes of the control mitochondria are not. In vivo the lipid-altered cells are able to incorporate radioactivity from [3-14C]- or [3-3H]serine into phosphatidylserine and phosphatidylcholine in amounts comparable to normal cells. Thus, under conditions of "stress" (e.g., the depletion of phosphatidylethanolamine), the phosphatidyltransferase is apparantly capable of utilizing other phospholipids besides its normal substrate phosphatidylethanolamine.
mesh_terms: D000818:Animals; D002262:Carboxy-Lyases / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D019884:Nitrogenous Group Transferases; D010714:Phosphatidylethanolamines / Q000378:metabolism; D010718:Phosphatidylserines / Q000096:biosynthesis / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism*; D010770:Phosphotransferases / Q000378:metabolism; D012694:Serine / Q000378:metabolism*; D013768:Tetrahymena / Q000201:enzymology / Q000378:metabolism*; D014166:Transferases / Q000378:metabolism; D017855:Transferases (Other Substituted Phosphate Groups)
chemical_list: D010714:Phosphatidylethanolamines; D010718:Phosphatidylserines; D010743:Phospholipids; D012694:Serine; D014166:Transferases; D019884:Nitrogenous Group Transferases; D010770:Phosphotransferases; D017855:Transferases (Other Substituted Phosphate Groups); C022350:phosphatidylethanolamine-L-serine phosphatidyltransferase; C022370:phospholipid serine base exchange enzyme; D002262:Carboxy-Lyases; C022353:phosphatidylserine decarboxylase