《细胞生物学》第4章 细胞质膜-教学课件（非AI生成）.ppt

Figure10-26.Thespectrin-basedcytoskeletononthecytoplasmicsideofthehumanredbloodcellmembrane.Thestructureisshownschematicallyin(A)andinanelectronmicrographin(B).Thearrangementshownin(A)hasbeendeducedmainlyfromstudiesontheinteractionsofpurifiedproteinsinvitro.Spectrindimersassociatehead-to-headtoformtetramersthatarelinkedtogetherintoanetlikemeshworkbyjunctionalcomplexescomposedofshortactinfilaments(containing13actinmonomers),tropomyosin（原肌球蛋白）,whichprobablydeterminesthelengthoftheactinfilaments,band4.1,andadducin（内收蛋白）.Thecytoskeletonislinkedtothemembranebytheindirectbindingofspectrintetramerstosomeband3proteinsviaankyrin（锚定蛋白）molecules,aswellasbythebindingofband4.1proteinstobothband3andglycophorin(notshown).Theelectronmicrographin(B)showsthecytoskeletononthecytoplasmicsideofaredbloodcellmembraneafterfixationandnegativestaining.(B,courtesyofT.ByersandD.Branton,PNSA.82:6153-6157)*Figure10-41.Simplifieddiagramofthecellcoat(glycocalyx).Thecellcoatismadeupoftheoligosaccharidesidechainsofglycolipidsandintegralmembraneglycoproteinsandthepolysaccharidechainsonintegralmembraneproteoglycans.Inaddition,adsorbedglycoproteinsandadsorbedproteoglycans(notshown)contributetotheglycocalyxinmanycells.Notethatallofthecarbohydrateisonthenoncytoplasmicsurfaceofthemembrane.cellcoat*Figure10-42.Theprotein-carbohydrateinteractionthatinitiatesthetransientadhesionofneutrophilstoendothelialcellsatsitesofinflammation.(A)ThelectindomainofP-selectinbindstothespecificoligosaccharideshownin(B),whichispresentonbothcell-surfaceglycoproteinandglycolipidmolecules.Thelectindomainoftheselectinsishomologoustolectindomainsfoundonmanyothercarbohydrate-bindingproteinsinanimals;becausethebindingtotheirspecificsugar