Membrane Domains

Abstract

Considerable evidence shows that lateral inhomogeneities in lipid composition and physical properties exist in biological membranes. These membrane lipid domains are proposed to play important roles in processes such as signal transduction and membrane traffic. However, there is not at present an adequate description of the nature of these lipid domains in terms of their size, abundance, composition, or dynamics. We discuss the current analyses of the properties and function of membrane domains in cells and compare their properties with chemically simpler model membrane systems that can be understood in greater detail.

Fluorescence Techniques Using Dehydroergosterol to Study Cholesterol Trafficking

“…Biochemical studies also support this concept and demonstrate that purified cholesterol-rich microdomains isolated from cultured cell (L-cell, MDCK, primary hepatocytes) represent nearly one-third of the plasma membrane, are rich in cholesterol as well as saturated/ monounsaturated fatty acylated phospholipids, and are comprised of physically distinct, liquidordered membrane phases intermediate between fluid liquid-crystalline and rigid gel phases (26,82,102,136,172,182,(215)(216)(217). Studies with purified microdomains from L-cell and MDCK plasma membranes showed that both exogenous (e.g.…”

Rafts in oligodendrocytes: Evidence and structure–function relationship

“…Rather, it is a non-ideal liquid mixture of molecules with variable degrees of mutual miscibility (Kusumi et al, 2004). As a consequence, the cell membrane contains a variety of molecular complexes and domains, characterized by different composition and spatial arrangement of the membrane-constituting lipids, which implies constraints on the diffusion of the membrane components (Kusumi et al, 2004;Lommerse et al, 2004;Mukherjee and Maxfield, 2004;Ritchie and Kusumi, 2004;Simons and Vaz, 2004;Vereb et al, 2003).…”

“…Ligand binding and cross-linking of raft-preferring molecules could induce "receptor-clustered rafts". These larger and stabilized rafts are thought to have a sufficient size and lifetime (up to 1-10h) to facilitate the incorporation of various key signaling molecules which in turn may result in downstream signaling (Brown and London, 1998;Brown and London, 2000;Kusumi et al, 2004;Kusumi et al, 2005;Mukherjee and Maxfield, 2004;Simons and Ikonen, 1997).…”

Oxidation–reduction respiratory chains and ATP synthase complex are localized in detergent-resistant lipid rafts

“…Therefore, specific membrane compartments are required in order to concentrate and organize these signal molecules. These specific membrane compartments, also commonly referred to as the lipid rafts, are composed of cholesterol and glycolipids [1,2], and predominantly harbor a host of receptors and signaling molecules, allowing them to mediate a variety of cellular events, including cellular signaling, pathogenic invasion, immune responses, and cholesterol homeostasis [3][4][5][6]. Because the lipid rafts are loaded with many receptors for epidermal growth factor (EGF) [7], platelet-derived growth factor [8], nerve growth factor [9], insulin [10], insulin-like growth factor [11], transforming growth factor [12], and tumor necrosis factor [13], these rafts might act as platforms which initiate various cellular signal pathways.…”