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Effects of dolichol on membrane permeability
J A Monti1, S T Christian, J S Schutzbach
1Department of Psychiatry, University of Alabama at Birmingham 35294.
Biochimica Et Biophysica Acta
|November 27, 1987
Summary
Dolichols significantly increase the permeability of phospholipid bilayers containing phosphatidylethanolamine to divalent cations. This effect is temperature-dependent, even in the absence of a lipid phase transition.
Area of Science:
- Biochemistry
- Membrane Biophysics
- Lipid Chemistry
Background:
- Phospholipid bilayers form the fundamental structure of cell membranes.
- Dolichols are involved in glycosylation pathways but their role in membrane permeability is less understood.
- Understanding lipid-protein interactions is crucial for cell function.
Purpose of the Study:
- To investigate the effect of dolichol incorporation on the permeability of phospholipid bilayers.
- To determine the influence of temperature on dolichol-mediated membrane permeability.
- To elucidate the role of dolichol in membranes containing phosphatidylethanolamine.
Main Methods:
- Preparation of small unilamellar vesicles (SUVs) using sonication.
- Incorporation of plant phosphatidylethanolamine, phosphatidylcholine, and dolichol into vesicles.
- Assay using calcein as a fluorescent probe and cobalt ions for fluorescence quenching.
- Temperature-dependent permeability measurements.
Main Results:
- Vesicles containing dolichol showed increased permeability to cobalt ions.
- Permeability increased 17-fold between 15 and 35°C, independent of phospholipid phase transitions.
- Dolichol distribution was uniform, and its presence was crucial for enhanced permeability.
Conclusions:
- Dolichols significantly modulate the permeability of phosphatidylethanolamine-containing phospholipid bilayers.
- Temperature plays a critical role in dolichol-induced changes in membrane permeability.
- Dolichol's influence on bilayer properties extends beyond its known role in glycosylation.