Journal of Lipid Research, Vol 29, 481-489, Copyright © 1988 by Lipid Research, Inc.

ARTICLES

Transbilayer movement of cholesterol in the human erythrocyte membrane

DL Brasaemle, AD Robertson and AD Attie
Department of Biochemistry, College of Agricultural and Life Sciences, University of Wisconsin-Madison 53706.

The rate of transbilayer movement of cholesterol was measured in intact human erythrocytes. Suspended erythrocytes were incubated briefly with [3H]cholesterol in ethanol at 4 degrees C, or with liposomes containing [3H]cholesterol over 6 hr at 4 degrees C to incorporate the tracer into the outer leaflet of erythrocyte plasma membranes. The erythrocytes were then incubated at 37 degrees C to allow diffusion of cholesterol across the membrane bilayer. Cells were treated briefly with cholesterol oxidase to convert a portion of the outer leaflet cholesterol to cholestenone, and the specific radioactivity of cholestenone was determined over the time of tracer equilibration. The decrease in specific radioactivity of cholestenone reflected transbilayer movement of [3H]cholesterol. The transbilayer movement of cholesterol had a mean half-time of 50 min at 37 degrees C in cells labeled with [3H]cholesterol in ethanol, and 130 min at 37 degrees C in cells labeled with [3H]cholesterol exchanged from liposomes. The cells were shown, by the absence of hemolysis, to remain intact throughout the assay. The presence of 1 mM Mg2+ in the assay buffer was essential to prevent hemolysis of cells treated with cholesterol oxidase perturbed the cells, resulting in an accelerated rate of apparent transbilayer movement. Our data are also consistent with an asymmetric distribution of cholesterol in erythrocyte membranes, with the majority of cholesterol in the inner leaflet.
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				S.-L. Niu and B. J. Litman Determination of Membrane Cholesterol Partition Coefficient Using a Lipid Vesicle-Cyclodextrin Binary System: Effect of Phospholipid Acyl Chain Unsaturation and Headgroup Composition Biophys. J., December 1, 2002; 83(6): 3408 - 3415. [Abstract] [Full Text] [PDF]

				T. L. Steck, J. Ye, and Y. Lange Probing Red Cell Membrane Cholesterol Movement with Cyclodextrin Biophys. J., October 1, 2002; 83(4): 2118 - 2125. [Abstract] [Full Text] [PDF]

				K. John, J. Kubelt, P. Muller, D. Wustner, and A. Herrmann Rapid Transbilayer Movement of the Fluorescent Sterol Dehydroergosterol in Lipid Membranes Biophys. J., September 1, 2002; 83(3): 1525 - 1534. [Abstract] [Full Text] [PDF]

				F. Schroeder, A. M. Gallegos, B. P. Atshaves, S. M. Storey, A. L. McIntosh, A. D. Petrescu, H. Huang, O. Starodub, H. Chao, H. Yang, et al. Recent Advances in Membrane Microdomains: Rafts, Caveolae, and Intracellular Cholesterol Trafficking Experimental Biology and Medicine, November 1, 2001; 226(10): 873 - 890. [Abstract] [Full Text] [PDF]

				G. van Meer Caveolin, Cholesterol, and Lipid Droplets? J. Cell Biol., March 5, 2001; 152(5): F29 - F34. [Abstract] [Full Text] [PDF]

				K. Simons and E. Ikonen How Cells Handle Cholesterol Science, December 1, 2000; 290(5497): 1721 - 1726. [Abstract] [Full Text]

				P. G. Yancey, W. V. Rodrigueza, E. P.C. Kilsdonk, G. W. Stoudt, W. J. Johnson, M. C. Phillips, and G. H. Rothblat Cellular Cholesterol Efflux Mediated by Cyclodextrins. DEMONSTRATION OF KINETIC POOLS AND MECHANISM OF EFFLUX J. Biol. Chem., July 5, 1996; 271(27): 16026 - 16034. [Abstract] [Full Text] [PDF]

				B. P. Atshaves, O. Starodub, A. McIntosh, A. Petrescu, J. B. Roths, A. B. Kier, and F. Schroeder Sterol Carrier Protein-2 Alters High Density Lipoprotein-mediated Cholesterol Efflux J. Biol. Chem., November 17, 2000; 275(47): 36852 - 36861. [Abstract] [Full Text] [PDF]