細胞生物學05.08-11mcbcells into tissues i廈門課件

1、廈門大學細胞生物學課件Part IV Cell Growth and DevelopmentHarvey Lodish et.al Molecular Cell Biology7ed.Ch20 Integrating Cells Into Tissues*Ch21 Stem cells, Cell Asymmetry, and Cell Death *Ch22 Nerve CellsCh23 ImmulologyCh24 Cancer *袁立 教授Room : D322, Tel: 2182019Email: Ch20 Integrating Cells Into TissuesHuman:

2、1015 cells, 265 cell typesphysiological functions cell typesCell differentiationtissues organs Cell differentiation: a developmental process in which compositions, structures and functions e increasingly specialized. Molecular base: differential gene expression- tissue-specific genes activated.Cell

3、types: identified by compositions, structures and functions, and often with morphologies. Tissues: aggregated with a given type of cells that cooperatively to perform a common function. Five major class: epithelial tissue, connective tissue, muscular tissue, nervous tissue and Blood.Organs: structur

4、al unit organized with different tissues to perform one or more specific functions. Notes：(skip)SpeciesCell numbersCell TypesVolvox (團藻)1022Porifer (海綿)1035-10C. elegans (線蟲)95912Hydra (水螅)10510-20Planaria (渦蟲)109100Human(人) 1015265Number and type of cells in some speciesCell to Cell : CAMs to CAMsC

5、ell to Matrix: Receptor to ECMspecific and distinctive interactions in different cells and tissuesAssembly of distinct tissues/organsdetermined by Molecular interactions at the cellular level Adhesive molecules（黏著性分子）: ：(adhesion黏著)（Adhesive interaction黏著反應）Cell-adhesion molecules (CAMs)(細胞黏著分子)Cell

6、-adhesion receptors （細胞黏著受體）Components in extracellular matrix(ECM) (細胞外基質(zhì))*黏（粘）著= 黏（粘）附20.1 Cell-Cell and Cell-Matrix Adhesion: an OverviewFigure 20.1 major cell-cell and cell-matrix adhesive interactions.major cell-cell and cell-matrix adhesive interactionsCell-adhesion molecules bind to one anoth

7、er and to intracellular proteins.Major families of CAMs and adhesion receptors: 4 major families(Fig 20.2) CAMs mediate adhesive interactions between cells through their extracellular domains; and the interactions can be:Homotypic adhesion or Homophilic bindingHeterotypic adhesion Heterophilic bindi

8、ngCell typeCAM class同、異型黏著同、異親型結(jié)合(Extended explanations on fig 20.2)-1 The adhesion can be tight and long lasting or week and transient.The functional adhesive molecules for interactions can be monomers or dimers(homo- or heterodimers)The 4 major families of CAMs and adhesion receptors :Cadherins (C

9、AMs) 鈣黏蛋白/素 Homophilic heterophilic ; Ca2+-dependent . (1)Cadherins 鈣黏蛋白/素 Cell-cell Adherens junction (2) Desmosomal cadherins Cell-cell desmosomes or 橋粒鈣黏蛋白 Cell-matrix hemidesmosomes (E-cadherins homophilic binding shown in fig.)Ig-superfamily CAMs (Ig-SF CAMs) Homophilic or heterophilic; as 免疫球蛋

10、白超家族/N-細胞黏著分子 cell-adhesion receptors or as CAMs; Ca2+- independent. (NCAM shown in fig)Selectins 選擇素 Heteroophilic; cell-cell; contain a carbohydrate-binding lectin domain that recognize specialized sugar structure on glycoproteins or glycolipids on adjacent cells . （P-Selectins shown in fig）Integr

11、ins 整聯(lián)蛋白 Composed of - & - subunits; function as CAMs or cell- adhesion receptors that binds to very large multi-adhesive matrix proteins ; Ca2+-dependent .(Extended explanations on fig 20.2)-2 Cytosol-facing domain can recruit: adapter proteins that directly or indirectly connect CAMs to elements o

12、f the cytoskeleton; intracellular molecules that function in signaling pathways;intracellular molecules that function for cell movement or contraction In many cases, a complex will be assembled at inner surface facilitated two-way (outside-in & inside-out) communications(Extended explanations on fig

13、 20.2)-3 Model for the generation of cell-cell adhesionsFig 20.3 Form clusterForm bound dimers, oligomersmonomer to mononmeroligomers to oligomers(Velcro-like adhesion)Formation of many cell-cell adhesions often entails two type of interactions:1st intercellular , adhesive, or trans interactions2nd

14、intracellular, lateral, or cis interactionsThe lateral monomer clustering may increase possibility of monomer to monomer or oligomer to oligomer trans interaction with the clustered CAMs on an adjacet cell. Formation of relatively week E-cadherin monomer to monomer trans interaction may precede late

15、ral clustering that strengthen the adhesion. Variables that determine the nature of adhesion: affinity, spatial distribution or density , activeness of the CAMs, as well as external forces (skip)(Explanations to fig 20.3)The Extracellular Matrix Participates in Adhesion, Signaling, and Other Functio

16、ns.20-1蛋白聚糖基底膜聚糖層粘蛋白纖連蛋白巢蛋白Major components of ECM膠原蛋白多黏基質(zhì)蛋白ECM：a complex combination of secreted proteins. - composition carefully controlled. diseases, if disturbed position & physical properties can vary depending on the tissue type, its location, and its physiological state, can be sensed by cel

17、l-adhesion receptors and then instruct cells to behave in response to their environment.- form a networks by binding to each other and communicate with cells by binding to cell- adhesion receptors. - involved in holding cells and tissues together; morphogenesis and forming tissues for specific purpo

18、ses at different anatomic sites; serving as a reservoir of extracellular signaling molecules, a lattice of cell migration, as a medium of cell-cell, cell-environment communications.Variation in the relative density of cells and ECM in different tissues（Fig 20.4）(Forming tissues for specific purposes

19、 at different anatomic sites)Dense connective tissueCells: fibroblastsMatrix：tightly packed ECM fibersSquamous epitheliumCells: epithelial cellsMatrix：little ECMECM function demonstration (E.g. Fig20.6 & 7 ) (a) WT salivary glands(b) fibronectin Ab-blockDwarfism with many skeletal elements shortened

20、 and disfiguredcartilage (blue), bone(red)Salivary glands branching blocked with fibronectin dysfunctionIntegrin adhesion receptor mediated signaling pathways that control diverse cell functions（Fig 20.8） The evolution of multifaceted adhesion molecules made possible the evolution of diverse animal

21、tissues.Conserved AM and functionsdiversityCell typesTissues/organsMore complex organismsGene dupliction &Divergent evlutionAlternative splicingAlternative splicing FamilesIsoformsKEY CONCEPTS of Section 20.1Cell-cell anal cell-extracellular matrix (ECM) interactions are critical for assembling cell

22、s into tissues, controlling cell shape and function, and determining the developmental fate of cells and tissues. Diseases may result from abnormalities in the structures or expression of adhesion molecules.Cell-adhesion molecules (CAMs) mediate direct cell-cell adhesions (homotypic and heterotypic)

23、, and cell-surface adhesion receptors mediate cell-matrix adhesions (see Figure 20-1). These interactions bind cells into tissues and facilitate communication between cells and their environments.The cytosolic domains of CAMs and adhesion receptors bind adapter proteins that mediate interaction with

24、 cytoskeletal fibers and intracellular signaling proteins.The major families of CAMs are the cadherins, selectins Ig-supsrfamily CAMs, and integrins (see Figure 20-2). Members of the integrin and Ig-CAM superfamilies can also function as adhesion receptors.tight cell-cell adhesions entail both cis (

25、lateral or intracellular) oligomerization of CAMs and trans (intercellular) interaction of like (homophilic) or different (heterophilic) CAMs (see Figure 20-3). The combination of cis and trans interactions produces a Velcro-like adhesion between cells.The extracelluar matrix (ECM) is a complex mesh

26、work of proteins and polysaccharides that contributes to the structure and function of a tissue. The major classes of ECM molecules are proteoglycans, collagens, and multi-adhesive matrix proteins (fibronectin, laminin).The evolution of adhesion molecules with specialized structures and functions pe

27、rmits cells to assemble into diverse classes of tissues with varying functions.Self review(skip)20.2 Cell-Cell and Cell-Matrix junctions and Their Adhesion MoleculesEpithelial cells have distinct apical, lateral, and basal surfacesThere 4 principle types of epithiliaPrincipal types of epithelia(a)單層

28、柱狀上皮; (c)變移上皮/移行上皮(b)單層扁平/鱗狀上皮; (d)復層扁平/鱗狀上皮Basolateral surfaceFig20.9Three types of junctions mediate many cell-cell and cell-ECM interactions(in animals)20-2(Occluding junctions)(comminicating junctions)In animals: 1) Anchoring junctions(錨定連接); 2)Tight junction(緊密連接), and 3) Gap junctions (縫隙連接).

29、In plant: plasmodesmata (胞間連絲).The anchoring junctions include 3 subtypes: (1) Adherens junctions (黏著連接), (2) Desmosomes(橋粒), (3) Hemidesmosomes (半橋粒).The tight junction and anchoring junctions perform the key task of cells and tissues together , and are organized into 3 parts: adhesive proteins in

30、the plasma membrane that connect one cell to another cell or to matrix (CAMs or adhesion receptors); adapter proteins (note listed in the table), which connect CAMs or adhesion receptors to the cytoskeletal filaments(細胞骨架微絲)and signaling molecules; the cytoskeletal filaments themselves.Notes to tabl

31、e 20.2 (I)(skip)The gap junctions permit rapid diffusion of small water-soluble molecules, including ions, betwwen adjacent cells(through connexon 連接子channels (connexin 連接蛋白), and are important for cell-cell plasma exchanges. Alone with tight junction and anchoring junctions, gap junctions share als

32、o a role of helping a cell communicate with its environment.The table listed also the principle involved CAMs or adhesion receptors, cytoskeletal attachments and the functions of the junctions, which we will discuss further detail later and you can use for your review. Adapter proteins may vary in d

33、ifferent cell types and are not listed. We will mentioned later in the further discussion of adhesive molecules with junctions.(skip)Notes to table 20.2 (II)Principal types of cell junctions connecting the columnar epithelial cells lining the small intestine. Fig 20.10 是，Cadherins mediate call-cell

34、adhesions in adherens junctions and desmosomesCadherins（鈣粘素）: (named for calcium-dependent adhesion) 100 members in the family and can be grouped into: Classical cadherins:Desmosomal cadherins:CDH1 - E-cadherin (epithelial)CDH2 - N-cadherin (neural)CDH3 - P-cadherin (placental)Desmoglein: DSG1, DSG2

35、, DSG3, DSG4Desmocollin： DSC1, DSC2, DSC3 Ungroupedcadherins: CDH4 - R-cadherin (retinal) CDH5 - VE-cadherin (vascular endothelial)CDH6 - K-cadherin (kidney)CDH13 - T-cadherin - H-cadherin (heart)CDH15 - M-cadherin (myotubule)CDH17 - LI cadherin (liver-intestine)Protocadherin:PCDH1;PCDH10; PCDH11X;

36、PCDH11Y; PCDH12;PCDHA1;PCDHA4;PCDHAC2; PCDHB5;PCDHGA11;PCDHGB3FAT; FAT2; FAT4.Fig 20.13 Protein constituents of typical adherens junctionsClassical CadherinsE- and N- Cadherins , are most wildly expressed, particularly during the early differentiation. Explanations to the fig 20-13(skip)Each contain

37、s a single transmembrane domain, a relatively short C-terminal cytosolic domain and five extracellular cadherin domains, witch are necessary for Ca2+ binding (between the repeat) and cell-cell adhesions.Their adhesions involve both cis and trans (heard to heard)interaction ( biding site at least inp

38、art in the most distal); and some minimal amount of Ca2+ in the extracellular fluid is required (binding site: between the repeats). preferably homophilic, but can mediate heterophilic interactions.The C-terminal is linked to the actin cytoskeleton by adapter proteins ( commonly - or - catenin); and

39、 interact with intracellular signaling molecules such as p120-catenin, - catenin(a dual role).Affacting cell aspects: cell-cell adhesion related, such as migration, epithelial-mesenchymal transition (EMT), etc.E.g. Fig 20.11 E-cadherin mediates Ca2+-dependent adhesion of L cellsE.g. Fig 20.12 E-cadh

40、erin mediates adhesive connections in cultured MDCK epithelial cells.(time :h )E.g. Fig 20.14 E-cadherin activity is lost during the epithelial-mesenchymal transition and cancer progression.Nomal MDCK (epithelial). cultureExpression of Smail (E-cadherin supressor) cause EMT(c)Section from a heredita

41、ry diffuse gastric cancer 遺傳性彌漫型胃癌.( E-cad.-DAB staining)Cancerous cellsDesosomal CadherinsDesosomes contain to specialized cadherin proteins: desmoglein橋粒芯膠蛋白 & desmocolin橋粒芯黏蛋白Plakoglobin橋粒斑珠蛋白desmoplakin橋粒斑蛋白Plakoghilns親橋粒斑蛋白Desosomal cadherins-Cytoplasmic plaque intermediate filamentsIntegrins m

42、ediate cell-ECM adhesions, including those in epithelial cell hemidesmosomesAnchoring simple columnar epithelial sheets to solid tissues and organs occurs via adhesion receptors integrins (see fig 20-2) which are located both within and outside of hemidesmosomes半橋粒 (see fig 20-10a) .Hemidesmosomes c

43、omprise several integral membrane proteins linked via cytoplasmic adapter proteins (a.g. plakins) to keratin-based intermediate filaments . The principle ECM adhesion receptor in epithelial hemidesmosomes is 64. Integrins function as adhesion receptors and CAMs in a variety of epithelial and nonepit

44、helial cells, mediating cell matrix and cell-cell interactions. In vertebrates at least 24 integrin herterodimers, composed of 18 types of subunits and 8 types of subunits.20-3， A single chain can interact with any one of the chains forming integrins that bind different ligands ( combinatorial diver

45、sity 組合多樣性). small number of components, large number of distinct functions. Although most cells express several distinct integrins, many integrins are expressed predominantly in certain types of cell. Many integrins bind more than one ligand and several of their ligands bind to multiple integrins.I

46、ntegrins typically exhibit low affinities for their ligands, However, binding of hundreds or thousands of integrin molecules to their ligands on the cells or matrix allows firm anchoring (velcro-like effects )Both subunits contribute to the primary extracellular ligand-binding site and Ca2+ are requ

47、ired for the bindingMost integrins are linked to the actin肌動蛋白 cytoskeleton via interaction of their cytoplasmic region of with adapter proteins. Including two of the integrins that connect the basal surface of the epithelial cells to the basal lamina via laminin 層粘蛋白. However , some cytoplasmic dom

48、ain interact with intermediate filaments such as the 4 of a64 in hemidesmosomes.Integrins can mediate outside- in and inside-out sgnaling, as we have already explained with fig 20-8. Integrin-mediate signaling pathways influence process as diverse as cell survival, cell proliferation, programmed cel

49、l deathTight junctions seal off body cavities and restrict diffusion of membrane componentsTight junction(Tj) ，also known as zonula occludens封閉小帶, between epithelial cells are usually located in a band surrounding the cells just below the apical surface. formingFigure 20.16a Frozen fracture preparat

50、ion of Tj between two intestinal epithelial cells a barrier that seal off body cavities Prevent the diffusion of macromolecules, and to varying degree small water soluble molecules and ions.Tjs help to maintain polarity by preventing diffusion of membrane protein & glycolipids.一，E.g. Fig 20-18Tj pre

51、vents the diffusion 鑭(稀土金屬)Lanthanum hydroxide (soluble, dark) administered from basolateral side of epi. C0uld not go through the Tj.，F(xiàn)igure 20.16b Schematic drawing of TjTjs are composed of thin bands (ridges脊線) of plasma-membrane proteins that completely encircle the cell Such proteins are cis ho

52、mophilic or heterophilic oligomerization of CAMsThe bands are in contact with similar bands on adjacent cells (trans or intercellular interaction of homophilic or heterophilic CAMs)Figure 20.17 Proteins mediating tight junctions（mainly Ig-SF CAMs)Tricelluin and a group of JAM, as well as a junctiona

53、l receptor CAR are recently identified in Tj formatopn.Each of JAMs & the CAR contains a single TM -helices.The two principle integral membrane proteins found in TJ: are occludin 閉合蛋白 and claudin 密封蛋白(a multigenefamily with 24 homologous). Each of these proteins has 4 TM -helices.1.閉合蛋白 2. 密封蛋白 3.三細

54、胞聯(lián)素4.連接黏附分子Tricelluinoccludin5.連接黏附分子 CARThe extracellular domain of rows of occludin ，claudin , and JAM form a extremely tight links with similar rows of the same proteins in the adjacent calls. Ca2+-dependent Caherin mediated adhesion also play an important role in Tj fomation, stability, and func

55、tion.The long C-teminal cytoplasmic segment of occludin and claudin binds to PDZ domain in some large cytosolic adapter proteins that mediate biding to other cytosolic proteins or to the C-termini of particular plasma-membrane proteins. There 250 PDZ domains found in about 100 proteins. The PDZ-doma

56、in can serve as scaffolds to assemble larger functional complexMovement of many nutrients across the intestinal epi. is in large part achieved through the transcellular pathway. Moreover, Tjs exhibit selective permeability.Transcellular and paracellular pathways of transepithelial transport.via spec

57、ific membrane-bund transport proteins. Via certain loops by specific claudin isforms Fig20-19 Gap junctions composed of connexins allow small molecules to pass directly between adjacent cellsGap junctions, the most common type of junction in animals, in virtually all contacting animal cells (except

58、skeletal muscle and blood cells). The most important feature of the junction is not the gap (up to 2-4nm) itself but a well-defined set of cylindrical particles (connexon連接子) that cross the gap and compose pores connecting to the cytoplasm of adjacent cells, which allows ions and other small soluble

59、 molecules to pass directly.In many tissue, anywhere from a few to thousands of gap junction particles cluster together in patches.Vertebrate gap junctions are composed of connexins連接蛋白, and pannexins泛連蛋白. (innexins & pannexins in invertebrates)Junction particles from a few to thousands cluster toge

60、ther in pitchesBetween 2 mouse liver cellsVertical viewCell-1Cell-2Figure 20.20ab EM graph3-4 nmHexagonal lookGap junctions forming a patch，二(c)Fig20.20cd +Current model of the structure of the gap junctionsX 66 + 6X 214 2000Da不通過；介于兩者間的 通過可不同和受限 Pannexin are also capable to form intercellular chann