Cholesterol displaces palmitoylceramide from its tight packing with Palmitoylsphingomyelin in the Absence of a Liquid-Disordered Phase

31Citations
Citations of this article
33Readers
Mendeley users who have this article in their library.

Abstract

A set of different biophysical approaches has been used to explore the phase behavior of palmitoylsphingomyelin (pSM)/cholesterol (Chol) model membranes in the presence and absence of palmitoylceramide (pCer). Fluorescence spectroscopy of di-4-ANEPPDHQ-stained pSM/Chol vesicles and atomic force microscopy of supported planar bilayers show gel Lb/liquid-ordered (Lo) phase coexistence within the range XChol = 0-0.25 at 22°C. At the latter compositional point and beyond, a single Lo pSM/Chol phase is detected. In ternary pSM/Chol/pCer mixtures, differential scanning calorimetry of multilamellar vesicles and confocal fluorescence microscopy of giant unilamellar vesicles concur in showing immiscibility, but no displacement, between Lo cholesterol-enriched (pSM/Chol) and gel-like ceramide-enriched (pSM/pCer) phases at high pSM/(Chol + pCer) ratios. At higher cholesterol content, pCer is unable to displace cholesterol at any extent, even at XChol < 0.25. It is interesting that an opposite strong cholesterol-mediated pCer displacement from its tight packing with pSM is clearly detected, completely abolishing the pCer ability to generate large microdomains and giving rise instead to a single ternary phase. These observations in model membranes in the absence of the lipids commonly used to form a liquid-disordered phase support the role of cholesterol as the key determinant in controlling its own displacement from Lo domains by ceramide upon sphingomyelinase activity. © 2010 by the Biophysical Society.

Cite

CITATION STYLE

APA

Busto, J. V., Sot, J., Requejo-Isidro, J., Goni, F. M., & Alonso, A. (2010). Cholesterol displaces palmitoylceramide from its tight packing with Palmitoylsphingomyelin in the Absence of a Liquid-Disordered Phase. Biophysical Journal, 99(4), 1119–1128. https://doi.org/10.1016/j.bpj.2010.05.032

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free