la203101y_si_005.avi (68.72 MB)
Making a Tool of an Artifact: The Application of Photoinduced Lo Domains in Giant Unilamellar Vesicles to the Study of Lo/Ld Phase Spinodal Decomposition and Its Modulation by the Ganglioside GM1
media
posted on 2011-12-20, 00:00 authored by Galya Staneva, Michel Seigneuret, Hélène Conjeaud, Nicolas Puff, Miglena I. AngelovaElectroformed giant unilamellar vesicles containing liquid-ordered Lo domains are important tools for the modeling of the physicochemical properties and biological functions of lipid rafts. Lo domains are usually imaged using fluorescence microscopy of differentially phase-partionioning membrane-embedded probes. Recently, it has been shown that these probes also have a photosensitizing effect that leads to lipid chemical modification during the fluorescence microscopy experiments. Moreover, the lipid reaction products are able as such to promote Lo microdomain formation, leading to potential artifacts. We show here that this photoinduced effect can also purposely be used as a new approach to study Lo microdomain formation in giant unilamellar vesicles. Photosensitized lipid modification can promote Lo microdomain appearance and growth uniformly and on a faster time scale, thereby yielding new information on such processes. For instance, in egg phosphatidylcholine/egg sphingomyelin/cholesterol 50:30:20 (mol/mol) giant unilamellar vesicles, photoinduced Lo microdomain formation appears to occur by the rarely observed spinodal decomposition process rather than by the common nucleation process usually observed for Lo domain formation in bilayers. Moreover, temperature and the presence of the ganglioside GM1 have a profound effect on the morphological outcome of the photoinduced phase separation, eventually leading to features such as bicontinuous phases, phase percolation inversions, and patterns evoking double phase separations. GM1 also has the effect of destabilizing Lo microdomains. These properties may have consequences for Lo nanodomains stability and therefore for raft dynamics in biomembranes. Our data show that photoinduced Lo microdomains can be used to obtain new data on fast raft-mimicking processes in giant unilamellar vesicles.
History
Usage metrics
Categories
Keywords
phase percolation inversionsphase separationsLo nanodomains stabilitybicontinuous phasestime scaleGiant Unilamellar VesiclesLo microdomain formationlipid raftsphotoinduced Lo microdomainsLo domainsphotosensitizing effectPhotoinduced Lo Domainsphotoinduced phase separationgm 1spinodal decomposition processganglioside GM 1Ganglioside GM 1Electroformed giant unilamellar vesicleslipid reaction productslipid chemical modificationfluorescence microscopy experimentsfluorescence microscopyphotoinduced effectLo microdomainsphysicochemical propertiesraft dynamicsLo microdomain appearancenucleation processLo domain formationdata showgiant unilamellar vesiclesPhotosensitized lipid modificationstudy Lo microdomain formationphotoinduced Lo microdomain formation
Licence
Exports
RefWorks
BibTeX
Ref. manager
Endnote
DataCite
NLM
DC