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Atomic Force Microscopy Imaging and Force Spectroscopy of Supported Lipid Bilayers
Published on: July 22, 2015
Lipid phase separation in phospholipid bilayers and monolayers modeling the plasma membrane
S R Shaikh1, A C Dumaual, L J Jenski
1Department of Biology, Indiana University-Purdue University at Indianapolis, 723 W. Michigan Street, Indianapolis, IN 46202-5132, USA.
Biochimica Et Biophysica Acta
|June 19, 2001
Summary
Docosahexaenoic acid-containing phospholipids may drive lipid phase separations in biological membranes. Cholesterol and sphingomyelin mixtures exhibit condensation, with cholesterol promoting phase separation in model plasma membranes.
Area of Science:
- Membrane biophysics
- Lipid self-assembly
Background:
- Biological membranes feature heterogeneous lipid distributions in microdomains.
- Docosahexaenoic acid-rich phospholipids are implicated in lipid phase separations.
Purpose of the Study:
- Investigate elastic and thermal properties of model plasma membranes.
- Examine phase separation behavior influenced by cholesterol and docosahexaenoic acid-rich phospholipids.
Main Methods:
- Monolayer pressure-area isotherms to assess condensation and elasticity.
- Differential scanning calorimetry (DSC) on bilayers to detect phase separations.
Main Results:
- Sphingomyelin and cholesterol mixtures show significant condensation.
- Cholesterol decreases, while docosahexaenoic acid-rich phospholipids increase, monolayer elasticity.
- Evidence of lipid 'squeeze out' suggests phase separation into distinct liquid phases.
- DSC confirms cholesterol induces phase separation even at low concentrations.
Conclusions:
- Docosahexaenoic acid-rich phospholipids contribute to lipid phase separation in model membranes.
- Cholesterol plays a key role in promoting phase separation into liquid ordered and disordered phases.
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