Lipid Dynamics and Domain Formation in Model Membranes Composed of Ternary Mixtures of Unsaturated and Saturated Phosphatidylcholines and Cholesterol

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Dag Scherfeld - (Author)
  • Nicoletta Kahya - , TUD Dresden University of Technology (Author)
  • Petra Schwille - , Chair of Biophysics (Author)

Abstract

In recent years, the implication of sphingomyelin in lipid raft formation has intensified the long sustained interest in this membrane lipid. Accumulating evidences show that cholesterol preferentially interacts with sphingomyelin, conferring specific physicochemical properties to the bilayer membrane. The molecular packing created by cholesterol and sphingomyelin, which presumably is one of the driving forces for lipid raft formation, is known in general to differ from that of cholesterol and phosphatidylcholine membranes. However, in many studies, saturated phosphatidylcholines are still considered as a model for sphingolipids. Here, we investigate the effect of cholesterol on mixtures of dioleoyl-phosphatidylcholine (DOPC) and dipalmitoyl-phosphatidylcholine (DPPC) or distearoyl-phosphatidylcholine (DSPC) and compare it to that on mixtures of DOPC and sphingomyelin analyzed in previous studies. Giant unilamellar vesicles prepared from ternary mixtures of various lipid compositions were imaged by confocal fluorescence microscopy and, within a certain range of sterol content, domain formation was observed. The assignment of distinct lipid phases and the molecular mobility in the membrane bilayer was investigated by fluorescence correlation spectroscopy. Cholesterol was shown to affect lipid dynamics in a similar way for DPPC and DSPC when the two phospholipids were combined with cholesterol in binary mixtures. However, the corresponding ternary mixtures exhibited different spatial lipid organization and dynamics. Finally, evidences of a weaker interaction of cholesterol with saturated phosphatidylcholines than with sphingomyelin (with matched chain length) are discussed.

Details

Original languageEnglish
Pages (from-to)3758-3768
Number of pages11
JournalBiophysical journal
Volume85
Issue number6
Publication statusPublished - Dec 2003
Peer-reviewedYes

External IDs

PubMed 14645066

Keywords

ASJC Scopus subject areas