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《Coexisting Domains in the Plasma Membranes of Live CellsCharacterized by Spin-Label ESR Spectroscopy活细胞质膜中的共存结构域 自旋标记ESR谱表征》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。
1、4452BiophysicalJournalVolume90June20064452–4465CoexistingDomainsinthePlasmaMembranesofLiveCellsCharacterizedbySpin-LabelESRSpectroscopyMustiJ.Swamy,LauraCiani,MingtaoGe,AndrewK.Smith,DavidHolowka,BarbaraBaird,andJackH.FreedDepartmentofChemistryandChemicalBiology,CornellUniversity,Ithaca,NewYork1485
2、3ABSTRACTTheimportanceofmembrane-basedcompartmentalizationineukaryoticcellfunctionhasbecomebroadlyappreciated,andanumberofstudiesindicatethattheseeukaryoticcellmembranescontaincoexistingliquid-ordered(Lo)andliquid-disordered(Ld)lipiddomains.However,thecurrentevidenceforsuchphaseseparationisindirect
3、,andsofartherehasbeennodirectdemonstrationofdifferencesintheorderinganddynamicsforthelipidsinthesetwotypesofregionsortheirrelativeamountsintheplasmamembranesoflivecells.Inthisstudy,weprovidedirectevidenceforthepresenceoftwodifferenttypesoflipidpopulationsintheplasmamembranesoflivecellsfromfourdiffe
4、rentcelllinesbyelectronspinresonance.Analysisoftheelectronspinresonancespectrarecordedoverarangeoftemperatures,from5to37°C,showsthatthespin-labeledphospholipidsincorporatedexperiencetwotypesofenvironments,LoandLd,withdistinctorderparametersandrotationaldiffusioncoefficientsbutwithsomedifferencesamon
5、gthefourcelllines.Theseresultssuggestthatcoexistenceoflipiddomainsthatdiffersignificantlyintheirdynamicorderintheplasmamembraneisageneralphenomenon.TheLoregionisfoundtobeamajorcomponentincontrasttoamodelinwhichsmallliquid-orderedlipidraftsexistina‘sea’ofdisorderedlipids.Theresultsonorderinganddynami
6、csforthelivecellsarealsocomparedwiththosefrommodelmembranesexhibitingco-existingLoandLdphases.INTRODUCTIONConsiderableevidencehasaccumulatedinrecentyearstovisualizeraftsonplasmamembranesofunstimulatedcellssupporttheviewthatlipid-dependentplasmamembranewithinthelimitsofopticalresolutionatthesametime
7、thatheterogeneityplaysimportantrolesincellularprocessesin-alargefractionoftheplasmamembraneappearstobe‘raft-cludingsignaltransductionandmembranetrafficking.like’basedondetergentinsolubilityandotherbiochemica
