The fluorescent cholesterol analog dehydroergosterol induces liquid-ordered domains in model membranes.
The fluorescent sterol dehydroergosterol (DHE) is often used as a marker for cholesterol in cellular studies. We show by vesicle fluctuation analysis that DHE has a lower ability than cholesterol to stiffen lipid bilayers suggesting less efficient packing with phospholipid acyl chains. Despite this difference, we found by fluorescence and atomic force microscopy, that DHE induces liquid-ordered/-disordered coexistent domains in giant unilamellar vesicles (GUVs) and supported bilayers made of dipalmitoylphosphatidylcholine (DPPC), dioleylphosphatidylcholine (DOPC) and DHE or cholesterol. DHE-induced phases have a height difference of 0.9-1 nm similar as known for cholesterol-containing domains. DHE not only promotes formation of liquid-liquid immiscibility but also shows strong partition preference for the liquid-ordered phase further supporting its suitability as cholesterol probe.
Garvik
Olav
O
MEMPHYS Center for Biomembrane Physics, Department of Chemistry and Physics, University of Southern Denmark, Odense M, Denmark.
Benediktson
Peter
P
Simonsen
Adam Cohen
AC
Ipsen
John Hjort
JH
Wüstner
Daniel
D
D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry; D002784:Cholesterol / Q000737:chemistry; D004875:Ergosterol / Q000031:analogs & derivatives* / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry; D008567:Membranes, Artificial; D008856:Microscopy, Fluorescence; D010713:Phosphatidylcholines / Q000737:chemistry; D053835:Unilamellar Liposomes / Q000737:chemistry
D005456:Fluorescent Dyes; D008051:Lipid Bilayers; D008567:Membranes, Artificial; D010713:Phosphatidylcholines; D053835:Unilamellar Liposomes; C010905:dehydroergosterol; D015060:1,2-Dipalmitoylphosphatidylcholine; D002784:Cholesterol; C017251:1,2-oleoylphosphatidylcholine; D004875:Ergosterol