Influence of cholesterol and ergosterol on membrane dynamics: a fluorescence approach☆
Section snippets
Materials and methods
Materials. DPPC and POPC were obtained from Avanti Polar Lipids (Alabaster, AL, USA). DMPC, cholesterol, ergosterol, and DPH were purchased from Sigma Chemical (St. Louis, MO, USA). All lipid stock solutions were made in methanol except ergosterol which was dissolved in ethanol. Phospholipids were checked for purity by thin layer chromatography on pre-coated silica gel plates (Sigma) in chloroform/methanol/water (65:35:5, v/v/v) and were found to give only one spot in all cases with a
Results
The change in fluorescence polarization of DPH with increasing sterol concentration is shown in Fig. 2. Fluorescence polarization is correlated to the rotational diffusion rate [25] of membrane embedded probes which is sensitive to the packing of fatty acyl chains and sterols. Fig. 2A shows that with increase in cholesterol concentration, the DPH polarization in fluid POPC membranes shows a continuous increase up to the highest concentration of cholesterol used. Thus, there is large (123%)
Discussion
Cholesterol is the major sterol molecule ubiquitously present in mammalian cells. It is hypothesized that cholesterol is selected in the long natural evolution process for its ability to optimize certain physical requirements of cell membranes (such as packing) in relation to functions performed by the cell [1], [38], [39]. Cholesterol appears to be the appropriate molecule to maintain a delicate balance between membrane rigidity to allow for large cell volumes (as found in higher eukaryotes)
Acknowledgements
This work was supported by the Council of Scientific and Industrial Research, Government of India. We gratefully acknowledge Satinder Rawat for preliminary experiments. We thank Y.S.S.V. Prasad and G.G. Kingi for technical help, and members of our laboratory for critically reading the manuscript. A.A. acknowledges the Indian Council of Medical Research for the award of a Project Assistantship. H.R. thanks the Council of Scientific and Industrial Research for the award of a Senior Research
References (51)
Cholesterol and the cell membrane
Biochim. Biophys. Acta
(1985)- et al.
Intracellular cholesterol transport and compartmentation
J. Biol. Chem.
(1995) - et al.
Cholesterol organization in membranes at low concentrations: effects of curvature stress and membrane thickness
Biophys. J.
(2001) - et al.
Looking at lipid rafts?
Trends Cell Biol.
(1999) Lipid rafts: elusive or illusive?
Cell
(2003)- et al.
Cholesterol is required for Leishmania donovani infection: implications in leishmaniasis
Mol. Biochem. Parasitol.
(2004) - et al.
Association of sterol- and glycosylphosphatidylinositol-linked proteins with Drosophila raft lipid microdomains
J. Biol. Chem.
(1999) Membrane “fluidity” as detected by diphenylhexatriene probes
Chem. Phys. Lipids
(1989)- et al.
A simple, specific spray for the detection of phospholipids on thin-layer chromatograms
J. Lipid Res.
(1964) An accurate and convenient organic phosphorus assay
Anal. Biochem.
(1971)
Light-scattering effects in the measurement of membrane microviscosity with diphenylhexatriene
Biophys. J.
Fluorimetric determination of critical micelle concentration avoiding interference from detergent charge
Anal. Biochem.
On the analysis of fluorescence decay kinetics by the method of least-squares
Anal. Biochem.
Effects of cholesterol on acyl chain dynamics in multilamellar vesicles of various phosphatidylcholines
Biochim. Biophys. Acta
Nanosecond fluorescence anisotropy decays of 1,6-diphenyl-1,3,5-hexatriene in membranes
Biochim. Biophys. Acta
Time-resolved fluorescence techniques: methods and applications in biology
Curr. Opin. Struct. Biol.
Hydration at the membrane protein–lipid interface
Biophys. J.
Dynamics of the hydrocarbon layer in liposomes of lecithin and sphingomyelin containing dicetylphosphate
J. Biol. Chem.
The evolution of membranes
The absence of sterol synthesis in insects
J. Biol. Chem.
GPI-anchored proteins and glycoconjugates segregate into lipid rafts in Kinetoplastida
FEBS Lett.
A spin label study of the effects of sterols on egg lecithin bilayers
Chem. Phys. Lipids
Molecular order and dynamics of phosphatidylcholine bilayer membranes in the presence of cholesterol, ergosterol and lanosterol: a comparative study using 2H-, 13C- and 31P-NMR spectroscopy
Biochim. Biophys. Acta
Fluorescence quenching in model membranes: an analysis of the local phospholipid environments of diphenylhexatriene and gramicidin A’
Biochim. Biophys. Acta
Sterol structure and membrane function
CRC Crit. Rev. Biochem.
Cited by (104)
The effects of the nature of the sterol on the properties and stability of niosome bilayer vesicles
2023, Journal of Molecular LiquidsNatamycin sequesters ergosterol and interferes with substrate transport by the lysine transporter Lyp1 from yeast
2022, Biochimica et Biophysica Acta - BiomembranesCitation Excerpt :Membrane ordering by cholesterol occurred in a slightly sigmoid fashion up to 50 mol% cholesterol, while condensation by ergosterol showed a plateau at around 25 mol% [29]. Also, fluorescence polarization studies using diphenylhexatriene found a concentration dependent saturation effect of ergosterol on lipid ordering in POPC membranes at around 20 mol% sterol, while for cholesterol, the ordering effect increased up to 50 mol% and in a sigmoidal manner [84]. The same trend was found for the membrane dipole potential as well as in bending rigidity measurements carried out with micropipette aspiration, where ergosterol was less effective in increasing the mechanical stability of POPC vesicles compared to cholesterol, particularly at high sterol mole fractions [24,85].
The role of the lipid environment in the activity of G protein coupled receptors
2022, Biophysical ChemistryEffect of the cholesterol on electroporation of planar lipid bilayer
2022, Bioelectrochemistry
- ☆
Abbreviations: DMPC, dimyristoyl-sn-glycero-3-phosphocholine; DPH, 1,6-diphenyl-1,3,5-hexatriene; DPPC, dipalmitoyl-sn-glycero-3-phosphocholine; MLV, multilamellar vesicle; POPC, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine.