Domain Formation and Stability in Complex Lipid Bilayers as Reported by Cholestatrienol

A1 Journal article (refereed)


Internal Authors/Editors


Publication Details

List of Authors: Y Jenny E Björkqvist, Thomas KM Nyholm, J Peter Slotte, Bodil Ramstedt
Publication year: 2005
Journal: Biophysical Journal
Volume number: 88
Issue number: 6
Start page: 4054
End page: 4063


Abstract

In this study, we used cholestatrienol (CTL) as a fluorescent reporter molecule to study sterol-rich Lo domains in complex lipid bilayers. CTL is a fluorescent cholesterol analog that mimics the behavior of cholesterol well. The ability of 12SLPC to quench the fluorescence of cholestatrienol gives a measure of the amount of sterol included in Lo domains in mixed lipid membranes. The stability of sterol-rich domains formed in complex lipid mixtures containing saturated sphingomyelins, phosphatidylcholines, or galactosylceramide as potential
domain-forming lipids were studied. The amount of sterol associated
with sterol-rich domains seemed to always increase with increasing temperature.
The quenching efficiency was highly dependent on the domain-forming
lipid present in complex lipid mixtures. Sphingomyelins formed stable
sterol-enriched domains and were able to shield CTL from quenching
better than the other lipids included in this study. The saturated
phosphatidylcholines also formed sterol-rich domains, but the quenching
efficiency in membranes with these was higher than with sphingomyelins
and the domains melted at lower temperatures. PGalCer was not able to
form sterol-enriched domains. However, we found that PGalCer stabilized
sterol-rich domains formed in PSM-containing bilayers. Using a
fluorescent ceramide analog, we also demonstrated that N-palmitoyl-ceramide displaced the sterol from sphingolipid-rich domains in mixed bilayer membranes.


Keywords

cholesterol, model membrane

Last updated on 2019-20-09 at 03:58