分子細(xì)胞生物學(xué)：9細(xì)胞骨架（師生）

1、Varied surface and interior structuresciliaflagellumA fibroblast in culture (attached); the red labels microfilamentsMovements of cellscrawlChemotaxis(video)A neutrophil in culture (semi-attached) CytoskeletonRef: Essential cell biology Chpt.17醫(yī)學(xué)細(xì)胞生物學(xué) 第五章第八節(jié)1. structure2. organization3. protein comp

2、onents and 4. functionsCytoskeleton in a cultured fibroblast (microtubules) A supportive networkArsenic oxide + Emodin treatment6h3h9h12h0hOxidative stress caused by emodin in combination with arsenic altered assembly of F-actin (confocal microscopy). Bar=10m. （Neoplasia. 2008, 10(1):41-51 ）Cytoskel

3、eton in dying cells (microfilaments)Changes in cell shape and attachmentTopic 1. Introduce the definition of cytoskeleton. Compare briefly the size and structure of microtubule, microfilament and intermediate filament? (10 min)Topic 2. Because the organelles and vesicles in the cells are transported

4、 as the cargos along the microtubules, the microtubule is called “highways in cells”. After learning the ways that the microtubule functions, give your comments to this metaphor, either supportive or opposite. (10 min)The cytoskeleton filaments are comprised of smaller protein subunits？Protofilament

5、s consist filaments.Fixed highway or changing ant trail?Changes of length and location：Assembly and disassembly（microtubules & microfilaments）The microfilaments in a deformed cellRearrangement=Disassembly- reassemblyinterphasemitosisThe microtubules in cells of interphase and mitosisRearrangemen

6、t=Disassembly- reassemblyMonomers PolymerenergyMonomersThe non-covalent bonds connects the monomers;Easy to form and break!解聚（depolymerization）聚合（polymerization）The monomer has the head and the tail; polymerization of the monomers makes the structural polarity of the polymers冰糖葫蘆: 山楂 or 梨Nucleation=

7、普通聚合預(yù)加“核”后聚合Nucleation is a speed-limited event for assemblyMonomers -oligomers -filament growingThe plus end grows faster than the minus endDynamic instability= switching back and forth between polymerization and depolymerizationThe fibers are growing then suddenly shrunkDynamic instabilityl Unlike

8、 our own bony skeleton, the cytoskeleton is a highly dynamic structure that is continuously reorganized as a cell changes shape, divides and responds to its environment.Topic 3. l List the major chemical components (the names of proteins) of, and the ways they are organized into, the microtubule, mi

9、crofilament and intermediate filament. (10 min)l How would you explain that the monomers of proteins that comprise the microtubules and microfilaments are global, but those comprise the intermediate filaments are linear? The proteins that comprise the microtubule:Tubulin (微管蛋白微管蛋白) ) （1）-tubulin het

10、erodimer （2）-tubulinu the monomer of microtubule polymer （3）-tubulin （only 1）-tubulin nucleationnucleationthe -tubulin ring complex，TuRCu每分子每分子-tubulin-tubulin和和 tubulintubulin各含有各含有一個(gè)一個(gè)GTP/GDT GTP/GDT 結(jié)合結(jié)合位點(diǎn)位點(diǎn)( (GTPGTP水解供應(yīng)水解供應(yīng)能量能量) )u異二聚體及其組異二聚體及其組成的原纖維有成的原纖維有極性極性-tubulin-tubulin-tubulin-tubulin每根原

11、纖維由每根原纖維由-tubulin-tubulin -tubulin -tubulin組成的異二聚體組成的異二聚體相接而成相接而成( (極性極性) )每根微管單管由每根微管單管由1313根原纖維圍成根原纖維圍成The forms of the microtubule:Cytoplasmic microtubulescentrolesCilium microtubulesnucleusThe centrosome decides the location and growing direction of the microtubule:The functions of the microtubu

12、leTopic 4. l Take 3 examples respectively to illustrate the functions of microtubules and microfilaments. (20 min)In sciatic nerve:Microtubules & intermediate filamentTransverse sectionlongitudinal sectionmovie1. Cell shape2. centrosome, spindle, basal body, cilia and flagellum3.Tracks of transp

13、ort and anchorage of organellesuTo maintain the shape and the organelle location of cells in interphase;uTo form the spindle to mediate cell division in mitosis微管微管高爾基體高爾基體中心體中心體細(xì)胞核細(xì)胞核電鏡下的中心粒：電鏡下的中心粒：9 9組三聯(lián)微管組三聯(lián)微管 movie= Motor proteins3. To provide tracks of transport and anchorage of organellesMoto

14、r proteins decide the directions of the vesicle transport 驅(qū)動蛋白驅(qū)動蛋白kinesinkinesin : toward the plus end: toward the plus end 動力蛋白動力蛋白dynein dynein : toward the minus end: toward the minus end卡通Motor proteins decide the directions of the vesicle transport 驅(qū)動蛋白驅(qū)動蛋白kinesinkinesin : toward the plus end:

15、toward the plus end 動力蛋白動力蛋白dynein dynein : toward the minus end: toward the minus endmicrotubulesERGolgi apparatuscentrosomenucleus3. To provide tracks of transport and anchorage of organellesorganellesmicrotubulesERGolgi apparatusTopic 5. Decipher the following micrograph (5 min) depolymerization

16、polymerizationTaxol binds with microtubulesBlockage of depolymerizationColchicine, nocodazolevinblastin bind with tubulinsBlockage of polymerizationAbnormality in microtubule formationTaxol binds with microtubulesBlockage of depolymerizationAbnormality in microtubule formationCancer cell divisionThe

17、 proteins that comprise the microfilament:Actin (肌動蛋白肌動蛋白)Microfilaments = actin filaments每分子每分子actinactin含有一含有一個(gè)個(gè)ATP/ADT ATP/ADT 結(jié)合位點(diǎn)結(jié)合位點(diǎn)( (ATPATP水解供應(yīng)能量水解供應(yīng)能量) )The functions of the microfilamentThe functions of the microfilament Actin-associated proteins (MAP) regulate actin polymerization and org

18、anization For the actin cytoskeleton to drive motility, the cell must be able to regulate actin polymerization and depolymerization. Actin-associated proteins: associate with monomers or filaments influence the organization of actin filaments in cellsStress fibers of fibroblastsMicrovilli (微絨毛微絨毛)in

19、 the epithelial cells of intestineCell crawling卡 通movieContractile ring in cell divisionMuscle contractionattachedreleasedcockedforce generatingattachedMuscle contractionFigure 17-42 Essential Cell Biology ( Garland Science 2010)解聚（depolymerization）聚合（polymerization）F-actinG-actinG-actinPhalloidin b

20、inds with actin filamentsBlockage of depolymerizationlatrunclin bind with actinsBlockage of polymerizationAbnormality in microtubule formation The two cytoskeletal systems can be bound together by linker proteins that attach microtubules to actin filaments.Interactions between microtubules and actin

21、 filamentsThe proteins that comprise the intermediate filament:Varied typesl Karatin l Vimentinl Laminl NFl Tissue specificityFigure 17-3 Essential Cell Biology ( Garland Science 2010)Ropelike filament, dont assemble/dissemble frequently The functions of the intermediate filament1. Cell shape2. Nucl

22、ear envelope 2）Cell junction and tissue integrityTo support plasma membrane and cell junctionmicrotubuleIFSimilar orientation with microtubulesInteraction with microtubulesFigure 17-7a Essential Cell Biology ( Garland Science 2010)Figure 17-2 Essential Cell Biology ( Garland Science 2010)IF: to main

23、tain cell junction and tissue integrityIntermediate filamentsCell junction: desmosomeTissue specificityThree cytoskeleton proteins are stained in a fibroblast Tubulin and Actin are highly conserved during eucaryotic evolution and existed in all eucaryotic cell types.Monomer: global Intermediate fila

24、ment proteins are not existed in all metazoans, not all cell type either. (Cell specific)Monomer: elongated Topic 3. l List the major chemical components (the names of proteins) of, and the ways they are organized into, the microtubule, microfilament and intermediate filament. l How would you explai

25、n that the monomers of proteins that comprise the microtubules and microfilaments are global, but those comprise the intermediate filaments are linear? (10 min)Topic 6. Decipher the following cartoon about 3 types of cytoskeleton, as a summary. (10 min)細(xì)胞質(zhì)骨架與疾病細(xì)胞質(zhì)骨架與疾病 細(xì)胞骨架的異?？梢鸷芏嗉膊?，特別是心細(xì)胞骨架的異常可引起很

26、多疾病，特別是心臟、骨骼肌、神經(jīng)系統(tǒng)的遺傳性疾病等。臟、骨骼肌、神經(jīng)系統(tǒng)的遺傳性疾病等。腫瘤細(xì)胞：旺盛的增殖、遷移能力和腫瘤細(xì)胞：旺盛的增殖、遷移能力和分化缺陷都與細(xì)胞骨架有關(guān)分化缺陷都與細(xì)胞骨架有關(guān) 干擾細(xì)胞骨架組裝的藥物作為抗癌藥干擾細(xì)胞骨架組裝的藥物作為抗癌藥()細(xì)胞質(zhì)骨架細(xì)胞質(zhì)骨架( (微管微管) )與疾病與疾病Nerve degenerative diseases微管相關(guān)蛋白tau磷酸化異常（微管組裝異常）： -老年癡呆(Alzheimer disease)體外培養(yǎng)細(xì)胞過度表達(dá)MAP2或 tau對微管束結(jié)構(gòu)的影響細(xì)胞質(zhì)骨架細(xì)胞質(zhì)骨架( (微絲微絲) )與疾病與疾病Heart dise

27、ases-肌動蛋白基因點(diǎn)突變：擴(kuò)張性心肌病-微絲相關(guān)蛋白基因點(diǎn)突變：家族性肥大性心肌病小鼠心臟：小鼠心臟：左正常左正常6月月右右myosin基因突變基因突變Arg403-Gln 心房肥大，通常生后數(shù)周死亡心房肥大，通常生后數(shù)周死亡細(xì)胞質(zhì)骨架細(xì)胞質(zhì)骨架( (中間絲中間絲) )與疾病與疾病Skin diseases -角蛋白基因突變: 單純性大泡性表皮松懈癥Nerve degenerative diseases-運(yùn)動神經(jīng)元中神經(jīng)絲組裝異常：肌萎縮性側(cè)索硬化癥 Microtubules are polarized polymers. The plus end is crowned by -tubul

28、in and assembles faster. The minus end is crowned by -tubulin and assembles slower.結(jié)構(gòu)結(jié)構(gòu)： 堿性微管結(jié)合區(qū)域堿性微管結(jié)合區(qū)域 酸性突出區(qū)域酸性突出區(qū)域微管結(jié)合蛋白（微管結(jié)合蛋白（MAPMAP）體外培養(yǎng)細(xì)胞過度表達(dá)MAP2或 tau對微管束結(jié)構(gòu)的影響微絲裝配中的成核作用微絲裝配中的成核作用q 與微管裝配需要與微管裝配需要TuRCTuRC成核作用類似，微絲裝成核作用類似，微絲裝配需要配需要ARP complex的成核作用的成核作用卡通q 與微管成核作用發(fā)生在與微管成核作用發(fā)生在細(xì)胞中央（中心體）細(xì)胞中央（中心體）不不同，微絲成核作用發(fā)生在同，微絲成核作用發(fā)生在