Effect of line tension on the lateral organization of lipid membranes
16 Nov 2007-Journal of Biological Chemistry (American Society for Biochemistry and Molecular Biology)-Vol. 282, Iss: 46, pp 33537-33544
TL;DR: The results revealed a linear increase of the temperature of domain formation and domain growth rate with line tension, and domain budding was shown to depend on height mismatch, which contribute significantly to knowledge of the physical-chemical parameters that control membrane organization.
About: This article is published in Journal of Biological Chemistry.The article was published on 2007-11-16 and is currently open access. It has received 380 citations till now. The article focuses on the topics: Membrane & Hydrophobic mismatch.
Citations
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TL;DR: The evidence for how this principle combines the potential for sphingolipid-cholesterol self-assembly with protein specificity to selectively focus membrane bioactivity is reviewed.
Abstract: Cell membranes display a tremendous complexity of lipids and proteins designed to perform the functions cells require. To coordinate these functions, the membrane is able to laterally segregate its constituents. This capability is based on dynamic liquid-liquid immiscibility and underlies the raft concept of membrane subcompartmentalization. Lipid rafts are fluctuating nanoscale assemblies of sphingolipid, cholesterol, and proteins that can be stabilized to coalesce, forming platforms that function in membrane signaling and trafficking. Here we review the evidence for how this principle combines the potential for sphingolipid-cholesterol self-assembly with protein specificity to selectively focus membrane bioactivity.
3,811 citations
TL;DR: This review summarizes current thinking on the nature of lipid rafts focusing on the role of proteomics and lipidomics in understanding the structure of these domains and the contribution of single-molecule methods in defining the forces that drive the formation and dynamics of these membrane domains.
484 citations
Cites background from "Effect of line tension on the later..."
...Studies have shown that the greater the difference in thickness between the two phases, the higher the line tension and this is associated, in turn, with the formation of larger rafts (40)....
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...It has been hypothesized that cell membranes stay close to the transition temperature for phase separation to allow better control of raft dynamics (40)....
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TL;DR: Early steps in steroid biosynthesis are addressed, including how cholesterol transport to the cholesterol-poor outer mitochondrial membrane (OMM) appears to involve cholesterol transport proteins, and how chronic steroidogenic capacity is determined by CYP11A1 gene transcription.
424 citations
TL;DR: In this article, the temperature dependence of line tension between liquid domains and of fluctuation correlation lengths in lipid membranes was quantitatively evaluated to obtain a critical exponent, nu = 1.2 +/- 0.2.
321 citations
TL;DR: The fluid mosaic model of Singer and Nicolson (1972) is a commonly used representation of the cell membrane structure and dynamics, but a number of features must be incorporated to obtain a valid, contemporary version of the model.
281 citations
Cites background from "Effect of line tension on the later..."
...For the case of different coexisting lipid domains in fluid phases, McConnell [92] proposed a theory, largely supported by later experimentation [93,94], according to which the shape and size of a given domain would be the result of an equilibrium between line tension and electrostatic dipole–dipole interactions....
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References
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TL;DR: A new aspect of cell membrane structure is presented, based on the dynamic clustering of sphingolipids and cholesterol to form rafts that move within the fluid bilayer that function as platforms for the attachment of proteins when membranes are moved around inside the cell and during signal transduction.
Abstract: A new aspect of cell membrane structure is presented, based on the dynamic clustering of sphingolipids and cholesterol to form rafts that move within the fluid bilayer. It is proposed that these rafts function as platforms for the attachment of proteins when membranes are moved around inside the cell and during signal transduction.
9,436 citations
TL;DR: This work will review the evidence that rafts exist in cells and focus on their structure, or the organization of raft lipids and proteins, and the role of rafts in signaling in hematopoietic cells.
2,312 citations
TL;DR: To test this hypothesis, peak-to-peak headgroup thicknesses h(pp) of bilayers were obtained from x-ray diffraction of multibilayer arrays at controlled relative humidities and showed that poly-cis unsaturated chain bilayers are thinner and more flexible than saturated/monounsaturated chain Bilayers.
1,725 citations
TL;DR: This review critically analyzes what is known of phase behavior and liquid-liquid immiscibility in model systems and compares these data with what isknown of domain formation in cell membranes.
Abstract: Views of how cell membranes are organized are presently changing. The lipid bilayer that constitutes these membranes is no longer understood to be a homogeneous fluid. Instead, lipid assemblies, termed rafts, have been introduced to provide fluid platforms that segregate membrane components and dynamically compartmentalize membranes. These assemblies are thought to be composed mainly of sphingolipids and cholesterol in the outer leaflet, somehow connected to domains of unknown composition in the inner leaflet. Specific classes of proteins are associated with the rafts. This review critically analyzes what is known of phase behavior and liquid-liquid immiscibility in model systems and compares these data with what is known of domain formation in cell membranes.
1,615 citations
TL;DR: It is shown that high-resolution fluorescence imaging using two dyes preferentially labelling different fluid phases directly provides a correlation between domain composition and local membrane curvature, which is able to provide experimental estimates of boundary tension between fluid bilayer domains.
Abstract: Lipid bilayer membranes--ubiquitous in biological systems and closely associated with cell function--exhibit rich shape-transition behaviour, including bud formation and vesicle fission. Membranes formed from multiple lipid components can laterally separate into coexisting liquid phases, or domains, with distinct compositions. This process, which may resemble raft formation in cell membranes, has been directly observed in giant unilamellar vesicles. Detailed theoretical frameworks link the elasticity of domains and their boundary properties to the shape adopted by membranes and the formation of particular domain patterns, but it has been difficult to experimentally probe and validate these theories. Here we show that high-resolution fluorescence imaging using two dyes preferentially labelling different fluid phases directly provides a correlation between domain composition and local membrane curvature. Using freely suspended membranes of giant unilamellar vesicles, we are able to optically resolve curvature and line tension interactions of circular, stripe and ring domains. We observe long-range domain ordering in the form of locally parallel stripes and hexagonal arrays of circular domains, curvature-dependent domain sorting, and membrane fission into separate vesicles at domain boundaries. By analysing our observations using available membrane theory, we are able to provide experimental estimates of boundary tension between fluid bilayer domains.
1,535 citations