Plasma membrane aminophospholipid distribution in transformed murine fibroblasts.
The possibility that the asymmetric distribution of aminophospholipids may be an intrinsic property of mammalian plasma membranes was examined in LM cells, a transformed murine fibroblast cell line. The cells were grown in suspension culture in a chemically defined medium without lipid, protein, or serum and then treated with 2,4,6-trinitrobenzenesulfonic acid (TNBS). A maximum of 4% of LM cell plasma membrane phosphatidylethanolamine and 5% of the phosphatidylserine was labelled with TNBS. Furthermore, long chain and unsaturated fatty acids were preferentially esterified to the non-derivatized phosphatidylethanolamine (inner monolayer) as compared to phosphatidylethanolamine derivatized with TNBS (outer monolayer). Isethionyl acetimidate, an alternative non-penetrating reagent, confirmed the results obtained with TNBS and provided supportive evidence for the highly asymmetric distribution of phosphatidylethanolamine; 6% of the phosphatidylethanolamine was labelled with isethionyl acetimidate. When the penetrating reagent methylacetimidate was used, more than 80% of the phosphatidylethanolamine was derivatized. Although the growing of the LM cells in 10% calf serum significantly increased plasma membrane phosphatidylcholine while decreasing phosphatidylethanolamine, calf serum had no significant effect on phosphatidylethanolamine or phosphatidylserine asymmetry.
D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism*; D002471:Cell Transformation, Neoplastic; D002794:Choline / Q000494:pharmacology; D005347:Fibroblasts; D007096:Imidoesters; D007513:Isethionic Acid / Q000031:analogs & derivatives; D007700:Kinetics; D051379:Mice; D008861:Microsomes / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D009578:Nitrobenzenes / Q000494:pharmacology*; D010714:Phosphatidylethanolamines / Q000378:metabolism; D010718:Phosphatidylserines / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism*; D014302:Trinitrobenzenesulfonic Acid / Q000494:pharmacology*
D007096:Imidoesters; D009578:Nitrobenzenes; D010714:Phosphatidylethanolamines; D010718:Phosphatidylserines; D010743:Phospholipids; C020761:isethionyl acetimidate; D014302:Trinitrobenzenesulfonic Acid; D007513:Isethionic Acid; D002794:Choline