期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2016
卷号：113
期号：49
页码：14025-14030
DOI：10.1073/pnas.1610705113
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：SignificanceThe use of methyl--cyclodextrin to fully replace endogenous sphingolipids and phospholipids in plasma membrane outer leaflets of living mammalian cells with exogenous natural and unnatural lipids is introduced in this paper. Outer leaflet lipid species were evaluated, with lipids exchanged out of the plasma membrane outer leaflet matching expected lipid asymmetry. The method will make possible a range of membrane structure/function studies. Our understanding of membranes and membrane lipid function has lagged far behind that of nucleic acids and proteins, largely because it is difficult to manipulate cellular membrane lipid composition. To help solve this problem, we show that methyl--cyclodextrin (MCD)-catalyzed lipid exchange can be used to maximally replace the sphingolipids and phospholipids in the outer leaflet of the plasma membrane of living mammalian cells with exogenous lipids, including unnatural lipids. In addition, lipid exchange experiments revealed that 70-80% of cell sphingomyelin resided in the plasma membrane outer leaflet; the asymmetry of metabolically active cells was similar to that previously defined for erythrocytes, as judged by outer leaflet lipid composition; and plasma membrane outer leaflet phosphatidylcholine had a significantly lower level of unsaturation than phosphatidylcholine in the remainder of the cell. The data also provided a rough estimate for the total cellular lipids residing in the plasma membrane (about half). In addition to such lipidomics applications, the exchange method should have wide potential for investigations of lipid function and modification of cellular behavior by modification of lipids.
