Cholesterol asymmetry in synaptic plasma membranes

• Published in: Journal of neurochemistry Vol. 116; no. 5; pp. 684 - 689
• Main Authors: Gibson Wood, W, Igbavboa, Urule, Müller, Walter E, Eckert, Gunter P
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-03-2011
• Subjects: Aging; Animals; Apolipoprotein E; Asymmetry; Caveolae; caveolin; caveolin-1; Cell Membrane - chemistry; Cell Membrane - metabolism; Cholesterol; Cholesterol - analysis; Cholesterol - metabolism; Ethanol; Fatty acid-binding protein; Fluidity; Humans; lipid domains; Lipid rafts; Lipids; lipoprotein receptors; Membrane Lipids - analysis; Membrane Lipids - metabolism; Membrane structure; Membranes; Models, Biological; Neurochemistry; P-Glycoprotein; Plasma membranes; Polyunsaturated fatty acids; statins; Sterols; Structure-function relationships; Synaptic Membranes - metabolism; Synaptic Membranes - ultrastructure
• ISSN: 0022-3042; 1471-4159
• DOI: 10.1111/j.1471-4159.2010.07017.x

J. Neurochem. (2011) 116, 684-689. ABSTRACT: Lipids are essential for the structural and functional integrity of membranes. Membrane lipids are not randomly distributed but are localized in different domains. A common characteristic of these membrane domains is their association with cholesterol. Lipid rafts and caveolae are examples of cholesterol enriched domains, which have attracted keen interest. However, two other important cholesterol domains are the exofacial and cytofacial leaflets of the plasma membrane. The two leaflets that make up the bilayer differ in their fluidity, electrical charge, lipid distribution, and active sites of certain proteins. The synaptic plasma membrane (SPM) cytofacial leaflet contains over 85% of the total SPM cholesterol as compared with the exofacial leaflet. This asymmetric distribution of cholesterol is not fixed or immobile but can be modified by different conditions in vivo: (i) chronic ethanol consumption; (ii) statins; (iii) aging; and (iv) apoE isoform. Several potential candidates have been proposed as mechanisms involved in regulation of SPM cholesterol asymmetry: apoE, low-density lipoprotein receptor, sterol carrier protein-2, fatty acid binding proteins, polyunsaturated fatty acids, P-glycoprotein and caveolin-1. This review examines cholesterol asymmetry in SPM, potential mechanisms of regulation and impact on membrane structure and function.