几种重要的信号转导通路.ppt

1、,Major Developmental signaling pathways RTK Pathways: FGF, EGF, Jak-Stat TGF-beta Wnt Hh Notch,6.10 Structure and function of a receptor tyrosine kinase,6.12 The widely used RTK signal transduction pathway,6.13 Activation of the Mitf transcription factor through the binding of stem cell factor by th

2、e Kit RTK protein (Part 2),Figure 16.4 Ligand-induced dimerization of HER1, a human receptor for epidermal growth factor (EGF).,Figure 16.5 Structure of the fibroblast growth factor (FGF) receptor, stabilized by heparan sulfate.,Figure 16.6 Activation of EGF receptor by EGF results in the formation

3、of an asymmetric kinase domain dimer.,Figure 16.7 The HER family of receptors and their ligands.,Figure 16.8 Erythropoietin and formation of red blood cells (erythrocytes).,6.14 A STAT pathway: the casein gene activation pathway activated by prolactin,Figure 16.27 Structure of TGF-b superfamily of s

4、ignaling molecules.,6.21 Relationships among members of the TGF- superfamily,6.21 Relationships among members of the TGF- superfamily (Part 1),6.21 Relationships among members of the TGF- superfamily (Part 2),6.23 The Smad pathway activated by TGF- superfamily ligands (Part 1),6.23 The Smad pathway

5、activated by TGF- superfamily ligands (Part 2),Figure 16.29 Model of Ski-mediated down-regulation of Smad transcription-activating function.,Genetic control of Drosophila embryogenesis,Edward B. Lewis Christiane Nuesslein- Volhard Eric Wieschaus,Wg:Green Hh: Red,Segment Polarity mutants wingless (wg

6、) hedgehog (hh),Figure 16.30 Wnt signaling pathway.,6.20 The Wnt signal transduction pathways (Part 1),6.20 The Wnt signal transduction pathways (Part 2),6.20 The Wnt signal transduction pathways (Part 3),Figure 16.31 Processing of Hedgehog (Hh) precursor protein.,Figure 16.32 Hedgehog signaling in

7、flies.,Figure 16.33 Hedgehog signaling in vertebrates.,Figure 16.34 (a) Activation of the NF-B signaling pathway.,Figure 16.34 (b) Activation of the NF-B signaling pathway.,6.26 Mechanism of Notch activity,Figure 16.35 Notch/Delta signaling pathway.,Figure 16.36 Proteolytic cleavage of APP and Alzhe

8、imers disease.,Figure 16.40 Multiple signal transduction pathways interact to regulate adipocyte differentiation.,Figure 15.6 GTPase switch proteins cycle between active and inactive forms.,Figure 15.7 Switching mechanism of G proteins.,Figure 15.15 General structure of G proteincoupled receptors.,F

9、igure 15.17 General mechanism of the activation of effector proteins associated with G proteincoupled receptors.,Experimental Figure 15.18 Activation of G proteins occurs within seconds of ligand binding in amoeba cells.,Figure 15.20 Activation of the muscarinic acetylcholine receptor and its effect

10、or K+ channel in heart muscle.,Figure 15.32 Activation of CREB transcription factor following ligand binding to Gs proteincoupled receptors.,Figure 15.34 Role of b-arrestin in GPCR desensitization and signal transduction.,Wildtype wingless sulfateless(sfl) sugarless (sgl),Phenotypes of sulfateless a

11、nd sugarless,The Gal-4/UAS technique,Enhancer Trap-Gal4,UAS-Gene X,X,Transcriptional Activation of Gene X,Tussue Specific Expression of Gal-4,UAS,Genomic Enhancer,Brand and Perrimon: Development (1993),Gene X,Glypican in Wnt signaling Haecker et al (1997) Development Lin and Perrimon (1999) Nature L

12、in et al (2001) Development Han et al (2004) Development Han et al (2005) Development Tao et al. (2005) Cell Yan et al. (2009) Dev Cell CK-1a in Wnt signaling Liu, et al (2002) Cell Pygopus (Pygo) in Wnt signaling: Belenkaya et al (2002) Development Schwab et al (2007) BMC Biology Song et al (2007)

13、Development,Wnt信号通路成员的鉴定,Morphogen (形态发生素) : An important concept in Biology,Turing, 1952,Morgan, 1897,发育过程中关键的形态发生素,Wnt / Wingless Hedgehog (Hh) TGF- / BMP FGF,特性 1. 进化上保守 2. 对胚胎发育至关重要 3. 功能异常与多种人类疾病密切相关,Cell proliferation and differentiation. (Driesch 1891, 1908) When he separated two sea urchin b

14、lastomeres, they produced two half-sized blastula, showing that cells are potentially independent, but function together to form a whole organism (Driesch 1891, 1908). (Morgan 1901). Morgan noted the polarity of organisms and that regeneration in worms occurs with different rates at different positi

15、ons. This led him to postulate that regeneration phenomena are influenced by gradients of “formative substances”,Morphogen,Morphogen,“ A form generating substance that diffuses through a tissue, its distribution dictating the development of cells in the tissue” Alan Turing (1952). The chemical basis

16、 of morphogenesis. Philos. Trans. R. Soc. Lond. B Biol. Sci. 237, 37-72,Growth Factor Morphogens,Signaling molecules produced in a restricted regions within a tissue. Morphogens emanate from their source to form a long-range concentration gradient. Receiving cells interpret morphogen gradient by act

17、ivating target gene expression at discrete concentration thresholds thereby acquiring positional information. Two criteria: 1. Concentration dependence. 2. Direct action at a distance Wnt, Hh, and TGF- are morphogens.,形态发生素功能失调相关的人类疾病,前脑无裂畸形 (HPE),骨发育不良,神经管发育缺陷,肾母细胞瘤,结肠癌,家族性渗出性玻璃体视网膜病变,骨质疏松-假性神经胶质瘤综

18、合症(OPS),裂足症,先天性四肢切断症,Vertebrates: SHh Wnt BMP,Hh, Wg, Dpp: essential morphogens in wing disc,Key questions for morphogen gradient formation (1) how do they secreted (2) how do they move (3) how do they establish their activity gradients,Models for morphogen Movement,Two main models Diffusion Transcy

19、tosis Other models Cytonemes Argosomes,Dpp is a morphogen in wing patterning,Dpp Sal Omb,P-MAD,UAS-GFP-Dpp Dpp-Gal4,Models on Dpp movement,A prevailing view is that Dpp moves across cells by planar transcytosis initiated by dynamin-mediated endocytosis. (Entchev, E. V., Schwabedissen, A., and Gonzal

20、ez-Gaitan, M. (2000). Cell 103, 981-991) However, mathematical modeling suggested that diffusive mechanism(s) is much more plausible than non-diffusive mechanisms. (Lander, A. D., Nie, Q., and Wan, F. Y. (2002). Dev Cell 2, 785-796) Question: Which mechanism controls Dpp movement?,Extracellular Dpp

21、gradient coincides with Dpp activity gradient in wing disc,Dynamin-mediated endocytosis,Dpp signaling is reduced cell-autonomously in dynamin-defective cells, but is normal in cells behind the dynamin-defective cells,Extracellular Dpp can move through dynamin-defective cells,Extracellular Dpp can mo

22、ve through dynamin-defective cells,Dynamin-mediated endocytosis,Is required for Dpp signaling Down-regulates extracellular Dpp levels Is not essential for Dpp movement,Structure of heparan sulfate proteoglycans,Gene Number in Drosophila,1,2 Dally Dally-like,1,Dpp fails to move across cells mutant fo

23、r sfl,sfl mutant clones,Dpp fails to move across cells mutant for or dally-dly,dally-dly mutant clones,Dpp fails to move across cells mutant for sfl or dally-dly,GFP-Dpp Extracellular Dpp Merge,sfl,dally-dly,The extracellular Dpp gradient represents Dpp activity gradient. Dynamin-mediated endocytosi

24、s is not required for Dpp movement, but is involved in Dpp signaling. The HSPGs Dally and Dly are required for Dpp movement. We propose that Dpp moves along the cell surface by attachment to the HSPGs Dally and Dly.,A model for Dpp movement across cells,形态发生素（Wnt、Hh、BMP）梯度形成机制 限制扩散机制,Wnt morpohgen:

25、Beag et al. (2001) Development Han et al. (2004) Development. Han et al. (2005) Development Tao et al. (2005) Cell Yan et al (2009) Developmental Cell Hh morphogen: Han et al (2004) Development Yan et al (2010) Development BMP morphogen: Belenkaya et al (2004) Cell,Wg acts as a morphogen in the wing

26、 disc,Dll Sens Merge,Extracellular Wg,Wnt Secretion Model in 2006,Wntless/Evi/Srt K. Balser lab (2006) Cell M. Boutros lab (2006) Cell E. Selva Lab (2007) Development,What is Retromer complex?,What does retromer do?,1. Retrieval of receptors from endosomes to Golgi,- Lysosomal hydrolases in mammalia

27、n cells,- Vacuolar hydrolases in yeast,2. Promoting of polymeric immunoglobulin receptor transcytosis,Known functions of retromer complex,Role of retrormer complex in Wingless signaling,Previous views: Retromer is required for Wnt signaling. Retromer controls Wnt signaling in its producing cells. Di

28、sruption of retromer affects Wnt gradient formation Retromer may control Wnt modifications or association with lipoproteins. Coudreuse et al. Science, 2006; Prasad et al. Development, 2006. Questions: How does retromer control Wnt signaling activity in Wnt producing cells?,Generation of dVps35 null

29、mutant and RNAi construct,Wg is accumulated in dVps35 mutant cells,dVps35 clones,UAS-dVps35 Ri /En-G4,Depletion of dVps35 decreases Wg secretion in S2 cells,Retromer is not required for Hh and Dpp functions,Hh distribution and signaling,Dpp signaling,In the absence of dVps35 activity:,Wg protein is

30、accumulated inside Wg-producing cells, but reduced on the cell surface of Wg-producing cells and in surrounding Wg-recieving cells. Wg protein levels are reduced in conditioned medium. Conclusion: Retromer is required for Wg secretion. Question: How Does Retromer regulate Wg secretion ?,Similarity b

31、etween dvps35 and Wls mutants,B,A,Wg,GFP,E-cad,merge,B,A,Wg,GFP,E-cad,merge,B,A,Wg,GFP,E-cad,merge,B,A,Wg,GFP,E-cad,merge,Hypothesis: Retromer may control Wg/Wnt secretion by regulating Wls activity,dVps35 interacts with Wls,Question:,What would happen with Wls in the absence of retromer?,Wls GFP Me

32、rge,Wls protein is reduced in the vps35 mutant cells,Retromer controls Wls stability,Wls-V5 Hh-G4/vps35 RNAi Wls-V5 Hh-G4/vps35 RNAi,Questions,What is the cellular distribution of Wls ? What is the role of retromer in regulating Wls activity?,Wls is distributed on the cell surface,Localization of Wl

33、s on cell membrane,Wls particles co-localize with endosome markers,Rab5-GFP Wls Merge,GFP-2xFYVE Wls Merge,Dynamin-mediated endocytosis,Wls is elevated on the plasma membrane of shi cells,shits1,Rab5 (RNAi),hrsd28,Wls DE-cad Merge,Dynamin-mediated endocytosis,Enhanced Wls levels in rab5 and hrs muta

34、nts,Question:,Does Retromer regulate Wnt secretion using similar mechanism(s) in vertebrate cells?,Depletion of Vps35 reduced Wnt3A and Wnt5A secretion,hWls forms a complex with Vps35,Human retromer complex controls the stability of hWls protein,Belenkaya et al. Developmental Cell 2008 Port et al. N

35、ature Cell Biology 2008 Yang et al. Developmental Cell 2008 Franch-Marro et al. Nature Cell Biology 2008 Pan et al. Developmental Cell 2008,Wnt Secretion Model in 2008,Question 1: Whats role of retromer in Wnt signaling Question 2: Mechanisms of Retrmer in Wnt secretion: Role of Snx3 in Wnt secretio

36、n Question 3: Roles of Retromer in other developmental patterning: Apical-Basal Polarity,What does Retromer do?,Homology between Human sorting nexins and Drosophila SNXs,Null allels of Drosophila SNX homologues,Generation of Dsnx3 Null mutants by P-element hopping,Dsnx3 is required for Wg secretion and signaling,Wg expression monitored by wg-lacZ is not altered,Extracellular Wg is reduced in the Dsnx3 mutant cells,