The phenyltetraene lysophospholipid analog PTE-ET-18-OMe as a fluorescent anisotropy probe of liquid ordered membrane domains (lipid rafts) and ceramide-rich membrane domains (original) (raw)
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Fluorescent polyene ceramide analogues as membrane probes
Langmuir : the ACS journal of surfaces and colloids, 2015
Three ceramide analogues have been synthesized, with sphingosine-like chains containing five conjugated double bonds. Pentaene I has an N-palmitoyl acyl chain, while the other two pentaenes contain also a doxyl radical, respectively at C5 (Penta5dox) and at C16 (Penta16 dox) positions of the Nacyl chain. Pentaene I maximum excitation and emission wavelengths in a phospholipid bilayer are 353 nm and 478 nm respectively. Pentaene I does not segregate from the other lipids in the way natural ceramide does, but rather mixes with them in a selective way according to the lipid phases involved. Fluorescence confocal microscopy studies show that, when lipid domains in different physical states coexist, Pentaene I emission is higher in gel than in fluid domains, and in liquid-ordered than in liquid-disordered areas. Electron paramagnetic resonance of the pentaene doxyl probes confirms that these molecules are sensitive to the physical state of the bilayer. Calorimetric and fluorescence quenc...
Chemistry & Biology, 2002
Gebze-Kocaeli 41470 applied probes for fluorescent labeling. In addition to high chemical and photochemical stability and high fluo-Turkey 2 Department of Chemistry rescence quantum yield, they should provide strong change of color in response to different membrane per-Kyiv National Shevchenko University 01033 Kiev turbations. In this sense the common polarity-sensitive [5] and electrochromic [6] dyes have very limited capa-3 A.V. Palladin Institute of Biochemistry 9 Leontovicha Street bilities, as these probes commonly provide the response by shifting one broad band that is present in emission, 01030 Kiev Ukraine and the magnitude of the shift is usually smaller than the bandwidth. In order to be sensitive to the two-band 4 Laboratoire de Pharmacologie et Physicochimie des Interactions Cellulaires et Molé culaires ratiometric probe, the dye is required to exhibit an excited-state reaction: isomerization, electronic charge UMR 7034 du CNRS Faculté de Pharmacie transfer, or proton transfer [7]
Monitoring Biophysical Properties of Lipid Membranes by Environment-Sensitive Fluorescent Probes
Biophysical Journal, 2009
We review the main trends in the development of fluorescence probes to obtain information about the structure, dynamics, and interactions in biomembranes. These probes are efficient for studying the microscopic analogs of viscosity, polarity, and hydration, as well as the molecular order, environment relaxation, and electrostatic potentials at the sites of their location. Progress is being made in increasing the information content and spatial resolution of the probe responses. Multichannel environment-sensitive probes that can distinguish between different membrane physicochemical properties through multiple spectroscopic parameters show considerable promise.
Chemistry and Physics of Lipids, 2012
The organization of lipids and proteins into domains in cell membranes is currently an established subject within biomembrane research. Fluorescent probes have been used to detect and characterize these membrane lateral heterogeneities. However, a comprehensive understanding of the link between the probes' fluorescence features and membrane lateral organization can only be achieved if their photophysical properties are thoroughly defined. In this work, a systematic characterization of N-(lyssamine Rhodamine B sulfonyl)-1,2-dioleoyl-sn-3-phosphatidylehanolamine (Rhod-DOPE) absorption and fluorescence behavior in gel, liquid-ordered (l o ) and liquid-disordered (l d ) model membranes was performed.
Biochimica et Biophysica Acta (BBA) - Biomembranes, 1988
The sudace density of the fluorescent probe N-(lissamine Rbodamine B sulfonyl)dipalmitoylphosphatidylcholine is the same in the two lipid leaflets of phosphatidylcholine bilayers containing the probe. In the liquid-crystalline state, the probe molecules aggregate above a threshold amount, approximately 0.2 mol/mol phospholipids. Above this threshold value, the surface density of the free probe molecules is constant, and all probe molecules added are incorporated in the aggregated form. The aggregation of the probe increases by approximately 20% when the medium pH is lowered to 4. In the gel state, the probe aggregation is higher than tlmt in the liquid-crystalline state, and the free probe molecules distribute unevenly in the bilayer surface. Even though the results obtained in our model system cannot be directly extrapolated to all model systems, we point out that care is to be taken in the use of the probe. In fact, only in membranes in the liquid-crystalline state in which the amount of probe molecules to phospholipid molecules is lower than 1 : 7 the fluorescence response of the probe is independent of the pH changes and of the molecular aggregation.
Fluorescence Studies of Dehydroergosterol in Phosphatidylethanolamine/Phosphatidylcholine Bilayers
Biophysical Journal, 1999
Our previous fluorescence study has provided indirect evidence that lipid headgroup components tend to adopt regular, superlattice-like lateral distribution in fluid phosphatidylethanolamine/phosphatidylcholine (PE/PC) bilayers , Biophys. J. 73:1967-1976). Here we have further studied this intriguing phenomenon by making use of the fluorescence properties of a sterol probe, dehydroergosterol (DHE). Fluorescence emission spectra, fluorescence anisotropy (r), and time-resolved fluorescence intensity decays of DHE in 1-palmitoyl-2-oleoyl-PC (POPC)/1-palmitoyl-2-oleoyl-PE (POPE) mixtures were measured as a function of POPE mole fraction (X PE ) at 23°C. Deviations, including dips or kinks, in the ratio of fluorescence peak intensity at 375 nm/fluorescence peak intensity at 390 nm (I 375 /I 390 ), fluorescence decay lifetime (), or rotational correlation time () of DHE versus PE composition plots were found at X PE Ϸ 0.10, 0.25, 0.33, 0.65, 0.75, and 0.88. The critical values at X PE Ϸ 0.33 and 0.65 were consistently observed for all measured parameters. In addition, the locations, but not the depth, of the dips for X PE Ͻ 0.50 did not vary significantly over 10 days of annealing at 23°C. The observed critical values of X PE coincide (within Ϯ0.03) with some of the critical mole fractions predicted by a headgroup superlattice model proposing that the PE and PC headgroups tend to be regularly distributed in the plane of the bilayer. These results agree favorably with those obtained in our previous fluorescence study using dipyrenylPC and Laurdan probes and thus support the proposition that 1) regular arrangement within a domain exists in fluid PE/PC bilayers, and 2) superlattice formation may play a significant role in controlling the lipid composition of cellular membranes (Virtanen et al., 1998, Proc. Natl. Acad. Sci. USA. 95:4964 -4969). The present data provide new information on the physical properties of such superlattice domains, i.e., the dielectric environment and rotational motion of membrane sterols appear to change abruptly as the lipid headgroups exhibit regular superlattice-like distributions in fluid bilayers.
Fluorescent Chemical Tools for Tracking Anionic Phospholipids
Anionic phospholipids are essential structural components of cell membranes. Spatiotemporal dynamics of these lipids play central roles in regulating signalling events, membrane trafficking, maintenance of cell-shape, and cargo transport. On the other hand, defects in anionic phospholipid metabolism are linked to multiple diseases. Hence, the ability to visualize these phospholipids and their dynamics in living cells can afford mechanistic insights into vital cell processes, guide the development of therapeutics, and lead to diagnostic agents. In this exciting backdrop, fluorescent sensors that can detect anionic phospholipids become key chemical tools that can be used to image and track these bio-molecules in a confocal microscopy platform. In this review, we highlight existing chemical probes and sensing strategies for anionic phospholipids along with their pros and cons in the context of their applicability toward imaging and tracking these essential lipids in living cells.
New BODIPY lipid probes for fluorescence studies of membranes
The Journal of Lipid Research, 2007
Many fluorescent lipid probes tend to loop back to the membrane interface when attached to a lipid acyl chain rather than embedding deeply into the bilayer. To achieve maximum embedding of BODIPY (4,4-difluoro-4bora-3a,4a-diaza-s-indacene) fluorophore into the bilayer apolar region, a series of sn-2 acyl-labeled phosphatidylcholines was synthesized bearing 4,4-difluoro-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene-8-yl (Me 4 -BODIPY-8) at the end of C 3 -, C 5 -, C 7 -, or C 9 -acyl. A strategy was used of symmetrically dispersing the methyl groups at BODIPY ring positions 1, 3, 5, and 7 to decrease fluorophore polarity. Iodide quenching of the phosphatidylcholine probes in bilayer vesicles confirmed that the Me 4 -BODIPY-8 fluorophore was embedded in the bilayer. Parallax analysis of Me 4 -BODIPY-8 fluorescence quenching by phosphatidylcholines containing iodide at different positions along the sn-2 acyl chain indicated that the penetration depth of Me 4 -BODIPY-8 into the bilayer was determined by the length of the linking acyl chain. Evaluation using monolayers showed minimal perturbation of ,10 mol% probe in fluid-phase and cholesterol-enriched phosphatidylcholine. Spectral characterization in monolayers and bilayers confirmed the retention of many features of other BODIPY derivatives (i.e., absorption and emission wavelength maxima near 498 nm and ?506-515 nm) but also showed the absence of the 620-630 nm peak associated with BODIPY dimer fluorescence and the presence of a 570 nm emission shoulder at high Me 4 -BODIPY-8 surface concentrations. We conclude that the new probes should have versatile utility in membrane studies, especially when precise location of the reporter group is needed.-Boldyrev, I. A., X. Zhai, M. M. Momsen, H. L. Brockman, R. E. Brown, and J. G. Molotkovsky. New BODIPY lipid probes for fluorescence studies of membranes. J. Lipid Res.
Biochemistry, 1974
Steady-state and time-resolved fluorescence anisotropy of 12-(9-anthroyl)stearic acid was examined in the presence of red blood cell membranes and phospholipid dispersions containing various amounts of cholesterol. The fluorescence emission spectrum, quantum yield, and fluorescence lifetime of AS are changed little by the presence of cholesterol. The rotational correlation time, 4 for 12-(9-anthroyl)stearic acid fluorescence anisotropy at 37" is 7.8 x 10-9 sec in normal red blood cells and 8.5 X low9 sec in blood cells containing twice the normal complement of cholesterol. A similar increase in 4 was observed in dipalmitoyllecithin vesicles containing high contents of cholesterol. The energy of activation for rotation of 12-(9-anthroyl)stearic acid is lowered by the A lthough there is no universally accepted model for membrane architecture, there is much evidence to indicate that many properties of membranes can be accounted for by a dynamic, fluid lipid bilayer structure (Gitler, 1972; Singer and Nicholson, 1972). Techniques used to detect the dynamic properties of the membrane include spin-label (