第4章-细胞质膜Appt课件

.,Chapter4-A,细胞质膜(PlasmaMembrane)结构模型与基本成分基本特征与主要功能,.,Themodelofanimalcells,.,Introduction,生物膜(Biomembrane)细胞质膜(PlasmaMembrane)/细胞膜(CellMembrane)细胞内膜(internalmembrane):内膜系统(EndomembraneSystem),细胞质膜:围绕细胞最外层，由脂质、蛋白质和糖类组成的生物膜。结构上作为细胞的界膜，功能上在细胞内外物质运输、能量转换、信息传递过程中起重要作用。,.,Modelsofmembranestructure,E.GorterandF.Grendel(1925)Lipidbilayer,“蛋白质-脂质-蛋白质”三明治式的质膜结构模型,有机溶剂抽提红细胞膜脂，测量面积,.,Modelsofmembranestructure,ROBERTSONJD.Theultrastructureofcellmembranesandtheirderivatives.BiochemSocSymp.1959;16:3-43.单位膜模型(unitmembranemodel),高锰酸钾或锇酸固定细胞,.,Modelsofmembranestructure,.,Modelsofmembranestructure,SJSingerandGLNicolson.Thefluidmosaicmodelofthestructureofcellmembranes.Science.(1972)175.720-731.,.,Modelsofmembranestructure,HendersonR,UnwinPN.Three-dimensionalmodelofpurplemembraneobtainedbyelectronmicroscopy.Nature.1975Sep4;257(5521):28-32.,古核生物盐细菌的质膜蛋白-菌紫红质(bacteriarhodopsin)的三维结构：7次跨膜蛋白，通过蛋白质的疏水结构域“镶嵌”在脂质双层中，利用光能完成质子的转运。,流动镶嵌模型强调：膜的流动性，即膜蛋白和膜脂均可侧向运动；膜蛋白分布不对称性，有的结合在膜表面，有的嵌入或横跨脂双分子层。,.,Modelsofmembranestructure,.,Modelsofmembranestructure,.,Modelsofmembranestructure,SimonsK,vanMeerG.Lipidsortinginepithelialcells.Biochemistry.1988Aug23;27(17):6197-202.,脂筏模型(lipidraftmodel):在甘油磷脂为主体的生物膜上，胆固醇、鞘磷脂等富集区域形成相对有序的脂相，如同漂浮在脂双层上的“脂筏”一样载着执行某些特定生物学功能的各种膜蛋白。最初可能在高尔基体上形成，最终转移到细胞质膜上。推测100nm的脂筏上可载有600个蛋白质分子。,.,Modelsofmembranestructure,生物膜结构总结：脂双分子层是组成生物膜的基本结构成分：磷脂的特性、流动性；蛋白质分子以不同的方式镶嵌在脂双层分子中或结合在其表面：不对称性、协同作用；生物膜可看成是蛋白质在双层脂分子中的二维溶液：复杂性、可控性、多能性；生物膜在细胞完成生命活动中可进行三维空间改变：结构可塑性、拆迁重建；,.,Thechemicalcompositionofmembranes,Amphipathic:两性分子;sphingolipids:鞘脂;sterols:甾醇动物细胞质膜上约有109个脂分子，约5X106/um2,.,Amphipathic:两性分子;sphingolipids:鞘脂;sterols:甾醇,(Plasmamembrane),(endoplasmicreticulum),(Lipidbilayer),2A.Membranelipids,.,2A.Membranelipids,erythrocyte:红细胞;myelin:髓磷脂;Phosphatidylcholine:磷脂酰胆碱/卵磷脂，PCPhosphatidylethanolamine:磷脂酰乙醇胺，PEPhosphatidylserine:磷脂酰丝氨酸，PS,.,2A.Membranelipids,.,2A.Membranelipids,Sphingosine(鞘氨醇),SM,PC,PS,PE,.,2A.Membranelipids,ChemicalstructureandbiosynthesisofPI,lipidsignalingcellsignalingmembranetrafficking,CDP-diacylglycerol,L-myo-inositol,.,2A.Membranelipids,Phosphatidylinositolmonophosphates:Phosphatidylinositol3-phosphate,PI(3)PPhosphatidylinositol4-phosphate,PI(4)PPhosphatidylinositol5-phosphate,PI(5)PPhosphatidylinositolbisphophosphates:Phosphatidylinositol3,4-bisphosphate,PI(3,4)P2Phosphatidylinositol3,5-bisphosphate,PI(3,5)P2Phosphatidylinositol4,5-bisphosphate,PI(4,5)P2orPIP2Phosphatidylinositoltrisphophosphate:Phosphatidylinositol3,4,5-trisphosphate,PI(3,4,5)P3orPIP3,.,2A.Membranelipids,鞘磷脂：Sphingosinemyelin，SM,Sphingolipidsgeneralstructures,.,2A.Membranelipids,Cerebroside:脑苷脂,ganglioside:神经节苷脂,Gal:半乳糖;GalNAc:乙酰半乳糖胺,.,2A.Membranelipids,.,2A.Membranelipids,.,2A.Membranelipids,膜脂运动方式：沿膜平面侧向运动脂分子围绕轴心的自旋运动脂分子尾部的摆动双层脂分子之间的翻转运动,.,2A.Membranelipids,脂质体,.,2A.Membranelipids,Figure4.9Liposomes.(a)Theseliposomalvesicles,whichrangeindiameterfromabout40-100nm,containtheanti-cancerdrugdoxorubicin(阿霉素).(b)Aschematicdiagramofastealthliposome.,聚乙烯二醇(polyethyleneglycol,PEG),.,2A.Membranelipids,磷脂在细胞信号转导中的功能,.,2B.MembraneProteins,膜蛋白与脂质双层的连接方式：整合蛋白与膜周蛋白Ptdinst:Phosphatidylinositol磷脂酰肌醇,.,2B.MembraneProteins,.,2B.MembraneProteins,.,2B.MembraneProteins,.,2B.MembraneProteins,.,2B.MembraneProteins,freeze-fracturereplication:冰冻断裂复型技术,.,2B.MembraneProteins,.,2B.MembraneProteins,.,2B.MembraneProteins,.,2C.MembraneCarbohydrates,.,2C.MembraneCarbohydrates,Glycocalyx,多糖蛋白复合体,.,2C.MembraneCarbohydrates,h