Testing and Thinkingl. Compare and contrast the extracellular matrix(ECM) of animal cells with the walls aroundplant cells.(a)What basic organizational principle underliesboth ECM and cell walls?(b) What are the chemical constituents in each case?()Whatfunctionalroles do the ECM and cell wallsharein common?(d) What functional roles are unigue to the ECM? Tothe cell wall?
1 Testing and Thinking 1. Compare and contrast the extracellular matrix (ECM) of animal cells with the walls around plant cells. (a)What basic organizational principle underlies both ECM and cell walls? (b) What are the chemical constituents in each case? (c) What functional roles do the ECM and cell wall share in common? (d) What functional roles are unique to the ECM? To the cell wall?
Question1. How might a liposome be prepared that could potentiallybe used in the treatment of a tumor whose cells have a proteincalled tumor cell antigen (TAG) in their membranes?2.Definediffusion. Include in your answer the thermodynamic driving forcefordiffusionand theenergyrequirement.3.Which of the situations shown below (A or B)will resultin a higherrate ofmovement ofthepositively charged solute acrossthe membraneand in which direction (circleA or B and draw an arrowto indicate thedirection ofmovement)?OUTSIDE++membraneINSIDEAB
2 Question 1. How might a liposome be prepared that could potentially be used in the treatment of a tumor whose cells have a protein called tumor cell antigen (TAG) in their membranes? 2. Define diffusion. Include in your answer the thermodynamic driving force for diffusion and the energy requirement. 3. Which of the situations shown below (A or B) will result in a higher rate of movement of the positively charged solute across the membrane and in which direction (circle A or B and draw an arrow to indicate the direction of movement)?
Answers:1.Make an antibody that recognizes the TAG protein and insert it into aliposomemembrane. Fill theinterior of the liposome with a chemical thatis toxic tothe cell. These liposomes should attach totumor cells and beinternalized after which the toxic chemicals should killthetumor cells2.Diffusion is the spontaneous movement of substances from high tolowconcentration, driven by entropy, no energy required.3.A has highest rate of movementA, from outside to inB, from inside to out3
3 Answers: 1. Make an antibody that recognizes the TAG protein and insert it into a liposome membrane. Fill the interior of the liposome with a chemical that is toxic to the cell. These liposomes should attach to tumor cells and be internalized after which the toxic chemicals should kill the tumor cells. 2. Diffusion is the spontaneous movement of substances from high to low concentration, driven by entropy, no energy required. 3. A has highest rate of movement A, from outside to in B, from inside to out
三、整联蛋白与ECM相互关系Integrins（整联蛋白、整合素）是大多数基质蛋白如胶原、纤连蛋白、层粘连蛋白等的受体。整联蛋白与ECM的结合是受体与配体的结合关系。整联蛋白为一大类跨膜糖蛋白，外连ECM（或细胞）内连细胞骨架，因而是ECM和细胞骨架之间的跨膜桥梁
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()整联蛋白的分子结构基质结合域α、β亚基，跨膜，异二聚体，β链细胞外是球形的头部，露出脂二价阳离子双分子层约20nm。头部可同细胞外半胱氨酸a链基质蛋白结合，富集区S细胞内的尾部同肌动蛋白相连质膜COOHHOOC胞质溶胶踝蛋白和a辅肌蛋白结合区10nm
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(二)整联蛋白的类型目前已经鉴定17种不同的α亚基和8种β亚基。从理论上推测应该有100种以上的α亚基和β亚基配对的整联蛋白，实际上只发现20种，提示这些亚基出现在细胞表面的位置可能具有特异性。整联蛋白同细胞外基质中粘着蛋白的识别与结合分为两种类型一类是同RGD区域结合另一类则不需要RGD区域
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RGD-COOH功能(三)纤粘连蛋白COOHHH,N作为跨膜接头在细胞外基质和细胞内肌动Ca钙结合位点Ca?RGD蛋白骨架之间起双向结合位点HN~Ga2+NH2β亚基联络作用，将细胞-NH2外基质同细胞内的骨a亚基重链二硫重复架网络连成一个整体，S-a亚基轻链同时还具有将细胞外信号向细胞内传递的作用胞质溶胶粘着斑蛋白将信号传递给细胞核踝蛋白粘着斑整联蛋白与胞外核蛋白激酶M纤连蛋白相连a辅肌动蛋白(FAK)DNA桩蛋白肌动蛋白纤维
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整联蛋白与胞外胶原纤维相连胶原纤维纤连蛋白整联蛋白质膜衔接器蛋白肌动蛋白丝
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细胞与细胞外基质epithelial cell表皮细胞sheetbasal lamina基膜collagen fiber胶原纤维macrophage巨噬细胞capillary毛细管elasticfiberfibroblast弹性纤维成纤维细胞mastcell肥大细胞glycosaminoglycansproteoglycans,andglycoproteins糖胺聚糖、蛋白聚糖、糖蛋白50μm
9 细胞与细胞外基质 毛细管 弹性纤维 肥大细胞 胶原纤维 表皮细胞 基膜 巨噬细胞 成纤维细胞 糖胺聚糖、蛋白聚糖、糖蛋白
研究表明，细胞外基质的生物学意义，不仅是将各种细胞连接在一起，赋予各种组织、器官的基本结构和形状，也赋予其力学性质，而且ECM在人体的发育、细胞分化与移行、信号转导等生理过程和炎症、损伤与修复、免疫应答以及肿瘤转移等病理过程中具有重要的功能和作用。ECM与临床疾病的关系也越来越受到人们的重视，《细胞外基质的分子生物学与临床疾病》作者：成军编著出版日期：1999-6-1出版社：北京医科大学出版社
10 研究表明，细胞外基质的生物学意义，不仅是将各种细 胞连接在一起，赋予各种组织、器官的基本结构和形状，也 赋予其力学性质。 而且ECM在人体的发育、细胞分化与移行、信号转导等 生理过程和炎症、损伤与修复、免疫应答以及肿瘤转移等病 理过程中具有重要的功能和作用。 ECM与临床疾病的关系也越来越受到人们的重视。 《细胞外基质的分子生物学与临床疾病》 作者: 成军 编著 出版日期: 1999-6-1 出版社: 北京医科大学出版社