Lateral diffusion in phospholipid bilayer membranes and multilamellar liquid crystals

Fahey, P. F.; Webb, Watt W.

doi:10.1021/bi00608a016

Cited by 179 publications

(139 citation statements)

References 53 publications

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“…First, ApoC-III diffuses rapidly when bound to fluid lipid bilayers. Its lateral diffusion coefficient is comparable to that for lipid analogs (3,4) and low molecular weight peptides (7) in fluid lipid bilayers (Table 2). In addition, the activation energies for diffusion for ApoC-III are similar for E-PtdCho and Pam2PtdCho when both are fluid (Table 1); and these energy values for ApoC-III mobility are similar to the values for lipid analog diffusion in E-PtdCho multibilayers (3).…”

Section: Methodsmentioning

confidence: 61%

“…The results have been communicated in a preliminary form (10). FRAP has been used so far to study a wide range of natural membrane (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21) and model membrane systems (3)(4)(5)(6)(7). It offers a convenient method for studying lateral diffusion and is particularly attractive from the points of view of experimental and theoretical simplicity (19,22).…”

mentioning

confidence: 99%

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Lateral mobility of an amphipathic apolipoprotein, ApoC-III, bound to phosphatidylcholine bilayers with and without cholesterol

Vaz

Jacobson

et al. 1979

Proc. Natl. Acad. Sci. U.S.A.

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The technique of fluorescence recovery after photobleaching was used to investigate the lateral mobility of a fluorescein-labeled amphipathic apolipoprotein, ApoC-II, bound to multibilayers prepared from dipalmitoyl phosphatidylcholine, egg phosphatidylcholine, and a 1:1 (molar ratio) mixture of egg phosphatidylcholine and cholesterol. In dipalmitoyl phosphatidylcholine bilayers the lateral diffusion coefficient (D) for the protein is about 2 X 10-9 cm2 sec1 at 200C and about 9 X 10-s cm2 sec1 at 450C. Plots The mobility of membrane components has drawn considerable attention in the recent literature (1, 2). Several reports on the lateral (3-7) and rotational diffusion (8, 9) of components in the plane of the membrane in model membrane systems have appeared. In model membranes, as opposed to biomembranes, it is possible in principle to examine simple membrane compositions-for example, one protein and one lipid membrane-and subsequently to increase the complexity of the system at will. In this manner, it is possible to learn about the influence of a given membrane component on the diffusion of other components in the membrane and also, by comparison to natural membrane diffusion results, to learn about the role that nonmembrane components in the cell play in the regulation of membrane component mobility.In the present communication we report the use of the technique of fluorescence recovery after photobleaching (FRAP) to study the lateral diffusion of an amphipathic apolipoprotein, ApoC-III, in bilayer membranes formed from dipalmitoyl phosphatidylcholine (Pam2PtdCho), egg-yolk phosphatidyl-choline (E-PtdCho), and an equimolar mixture of E-PtdCho and cholesterol (Chol). The results have been communicated in a preliminary form (10). FRAP has been used so far to study a wide range of natural membrane (11-21) and model membrane systems (3-7). It offers a convenient method for studying lateral diffusion and is particularly attractive from the points of view of experimental and theoretical simplicity (19,22).ApoC-III is an amphipathic peptide having a molecular weight of about 9000 and a known amino acid sequence (23,24). Its interaction with lipid membranes has been extensively studied (24). It interacts with E-PtdCho (25) MATERIALS AND METHODS ApoC-III was isolated according to the procedure of Brown et al. (28) and was labeled with fluorescein by reaction of the protein (1 mg/ml) in 0.1 M sodium borate buffer at pH 9.0 with a 100-fold molar excess of fluorescein isothiocyanate (Baltimore Biological Laboratory Division, Becton-Dickinson) for 1 hr at 250C. After reaction, the labeled protein (dye/protein ratio = 2) was separated from unreacted dye by filtration through a column of Sephadex G-25 using Dulbecco's Ca2+-and Mg2+-free phosphate-buffered saline.The phospholipids used in this study were isolated or synthesized by Tom Isac in the laboratory of D. Papahadjopoulos. Pam2PtdCho was synthesized as described by Robles and Van Den Berg (29) and E-PtdCho was isolated from egg yolks as described by Papah...

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Section: Methodsmentioning

confidence: 61%

mentioning

confidence: 99%

Lateral mobility of an amphipathic apolipoprotein, ApoC-III, bound to phosphatidylcholine bilayers with and without cholesterol

Vaz

Jacobson

et al. 1979

Proc. Natl. Acad. Sci. U.S.A.

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“…On blebs of L6 and FDB, we find that D has increased 2.7-fold (L6) and <15-fold (FDB) over the mobility on the normal cell surface, to yield similar values: D = (1 .2 ± 0.4) x 10 -8 cm2/s on L6, and D = (1.5 ± 0.6) x 10-e cm2/s on FDB, both with complete recovery. These diffusion coefficients for NBD-PC on blebs are encompassed by the range of our measurements of a variety oflipid analogs in lipid bilayer model membranes at physiological temperatures in multicomponent lipid mixtures (36). From these measurements we can conclude that membrane viscosity changes alone are not responsible for the changes of many orders of magnitude that we have found for the diffusibility of AChRs on FDB cells and Con A receptors on L6 cells, although the relatively small ninefold increase in the diffusion coefficient of AcRSD on L6 blebs may be partially attributable to the 2.7-fold decrease in viscosity as witnessed by the lipid probe diffusion.…”

Section: Discussionmentioning

confidence: 99%

Enhanced molecular diffusibility in muscle membrane blebs: release of lateral constraints.

Tank¹,

Wu²,

Webb³

1982

The Journal of Cell Biology

249

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Measurements of lateral molecular diffusion on blebs formed on the surfaces of isolated muscle cells and myoblasts are reported . These blebbed membranes retain integral proteins but apparently separate from the detectable cytoskeleton . On blebs, acetylcholine receptors, concanavalin A receptors, and stearoyldextran extrinsic model receptor molecules are free to diffuse with a diffusion coefficient (D) -3 x 10-9 cm'/s, which is close to the value predicted for hydrodynamic drag in the lipid membrane . In contrast, diffusion of these typical receptors in intact cell membranes is constrained to D :Z 10-10 cm2/s with substantial fractions virtually nondiffusible (D < 10-' 2 cm2/s) . Lipid analog diffusion is also slightly enhanced in blebs as expected of evanescent lipid protein interaction . This strong enhancement of membrane protein diffusion is attributed to release from unidentified natural constraints that is induced in some way by detachment of the bleb membrane .The lateral diffusion of plasma membrane components has become routinely accessible to measurement by fluorescence photobleaching recovery (FPR) (1) . Taken together, data accumulated for vertebrate cells in culture establish several distinctive common characteristics of lateral diffusibility of cell surface components (2--6) : (a) A substantial fraction of the population of each cell surface protein is not detectably diffusible over distances of several micrometers during an experimental interval ofhours . Thus the diffusible fraction (R) is said to be <100%, and it is often <75%. (b) Diffusion coefficients (D) of the diffusible fraction ofcell membrane proteins do not generally exceed 1 x 10-1°cm 2/s and are frequently much smaller. (Implied diffusive transit time across a 10-8m cell: 1/2 h.) (c) Plasma membrane lipid diffusibility is virtually complete over distances of several micrometers (R = 100%, except possibly in a few compartmentalized cell types) with diffusion coefficients of the order of 1 x 10-e cm2/s, i.e., usually >100 times faster than membrane proteins. (Implied diffusive transit time across a 10-N.m cell: 1/2 min.)Certain proteins are virtually nondiffusible in toto (R = 0%) on the cell surface. For example, the acetylcholine receptor (AChR) localized at neuromuscular junctions and in patches on myotubes (7,8), and frbronectin on the surface of cultured fibroblasts (9) .In contrast with the cell surface, protein molecules that are reconstituted into phospholipid model membranes diffuse nearly as fast as lipid molecules and with no immobile fraction.

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“…In fact, the very small value of the diffusion constant is numerically hard to determine accurately, but the overall drop by about two orders of magnitude is probably robust and corresponds well to what is known for typical phospholipid bilayers. 40 Thus we have a first transition from fluid to gel and a second transition at a lower temperature to a different gel phase. In order to understand what is actually occurring in the gel-gel transition we require a suitable order parameter, and it turns out that local lipid packing is what one has to look at.…”

Section: Constant W C Profiles: Gel-fluid Transitionmentioning

confidence: 94%

“…40 Taking an average value of about 0.01 2 / from our data, and using the length mapping Ϸ 1 nm ͑see above͒ we obtain a time scale mapping of Ϸ 10 ns. Although we do not place great quantitative weight on such an approximate calculation, it does serve to illustrate that the time scales accessible by us are extremely long, being of the order of milliseconds.…”

Section: -7mentioning

confidence: 99%

Solvent-free model for self-assembling fluid bilayer membranes: Stabilization of the fluid phase based on broad attractive tail potentials

Cooke

Deserno

2005

The Journal of Chemical Physics

246

411

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We present a simple and highly adaptable method for simulating coarse-grained lipid membranes without explicit solvent. Lipids are represented by one head bead and two tail beads, with the interaction between tails being of key importance in stabilizing the fluid phase. Two such tail-tail potentials were tested, with the important feature in both cases being a variable range of attraction. We examined phase diagrams of this range versus temperature for both functional forms of the tail-tail attraction and found that a certain threshold attractive width was required to stabilize the fluid phase. Within the fluid-phase region we find that material properties such as area per lipid, orientational order, diffusion constant, interleaflet flip-flop rate, and bilayer stiffness all depend strongly and monotonically on the attractive width. For three particular values of the potential width we investigate the transition between gel and fluid phases via heating or cooling and find that this transition is discontinuous with considerable hysteresis. We also investigated the stretching of a bilayer to eventually form a pore and found excellent agreement with recent analytic theory.

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Lateral diffusion in phospholipid bilayer membranes and multilamellar liquid crystals

Cited by 179 publications

References 53 publications

Lateral mobility of an amphipathic apolipoprotein, ApoC-III, bound to phosphatidylcholine bilayers with and without cholesterol

Lateral mobility of an amphipathic apolipoprotein, ApoC-III, bound to phosphatidylcholine bilayers with and without cholesterol

Enhanced molecular diffusibility in muscle membrane blebs: release of lateral constraints.

Solvent-free model for self-assembling fluid bilayer membranes: Stabilization of the fluid phase based on broad attractive tail potentials

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