1、信号传导与疾病（Signal transduction and disease）The Hallmarks of CancerCell-to-cell communication by extracellular signaling usually involves six stepssynthesis of signaling molecule by signaling cellrelease of the signaling molecule by the signaling celltransport of the signal to the target cellChanges in
2、targeted gene expression triggered by the receptor-signal complexremoval of the signal,which usually terminates the cellular responsedetection of the signal by a specific receptor protein细胞外因子通过与受体（膜受体或核受体）结合，细胞外因子通过与受体（膜受体或核受体）结合，引发细胞内的一系列生物化学反应，直至细胞生理引发细胞内的一系列生物化学反应，直至细胞生理反应所需基因的转录表达开始的过程。反应所需基因的转
3、录表达开始的过程。“wiring”of cell regulatory circuitsIntercellular Signaling:how cells communicate with one anotherIntracellularSignalingExamples of SignalingSYNAPTICPARACRINEENDOCRINEExtracellular Signals Bind to Different Types of Receptors 1951年，第一个生长因子神经生长因子年，第一个生长因子神经生长因子 NGF发现发现 Rita Levi-Montalcini&St
4、anley Cohen 1955年，年，Receptor 的概念正式提出的概念正式提出 1957年，第二信使年，第二信使cAMP发现发现 Earl Sutherland50 年代中期，年代中期，磷酸化的发现和第一个蛋白激酶的分离磷酸化的发现和第一个蛋白激酶的分离 Edwin Krebs&Fischer 70年代，年代，G蛋白和蛋白和G蛋白连接受体的发现和克隆蛋白连接受体的发现和克隆 Alfred G.Gilman&Martin Rodbell 发现癌基因发现癌基因v-src 的蛋白产物是蛋白酪氨酸激酶的蛋白产物是蛋白酪氨酸激酶 Michael Bishop&Harold E.Varmus简要回
5、顾简要回顾The Nobel Prize in Physiology or Medicine 1986for their discoveries of growth factors Stanley Cohen Rita Levi-Montalcini“for his discoveries concerning the mechanisms of the action of hormones”The Nobel Prize in Physiology or Medicine 1971Earl W.Sutherland,Jr.The Nobel Prize in Physiology or Me
6、dicine 1994Alfred G.Gilman Martin Rodbell for their discovery of G-proteins and the role of these proteins in signal transduction in cells for their discoveries concerning reversible protein phosphorylation as a biological regulatory mechanism The Nobel Prize in Physiology or Medicine 1992Edmond H.F
7、ischer Edwin G.Krebs The Nobel Prize in Physiology or Medicine 1989for their discovery of the cellular origin of retroviral oncogenes J.Michael Bishop Harold E.Varmus Robert F.Furchgott Louis J.Ignarro Ferid Murad“for their discoveries concerning nitric oxide as a signalling molecule in the cardiova
8、scular system The Nobel Prize in Physiology or Medicine 1999 细胞外因子细胞外因子受体受体联结蛋白联结蛋白G蛋白蛋白第二信使第二信使胞内激酶胞内激酶核受体核受体基本组成基本组成一一刺激细胞增殖的因子刺激细胞增殖的因子生长因子（生长因子（growth factor）是一类以刺激细胞生长为特征的多肽是一类以刺激细胞生长为特征的多肽 受体具有酪氨酸激酶活性 特异性 多样性 家族性 交叉性细胞因子（细胞因子（cytokine）白介素、血细胞刺激因子、干扰素 受体本身不具有激酶活性激素和神经递质激素和神经递质细胞外因子细胞外因子二二其他重要的细
9、胞外因子其他重要的细胞外因子抗原抗原肿瘤坏死因子（肿瘤坏死因子（tumor necrosis factor,TNF）粘附分子粘附分子(adhesion molecules)纤粘连蛋白（纤粘连蛋白（Fibronectine,Fn）层粘连蛋白（）层粘连蛋白（laminin,Lm）胶原蛋白（胶原蛋白（collagen,coll）细胞外因子细胞外因子受体受体 酪氨酸激酶受体（酪氨酸激酶受体（Receptor Tyrosine Kinases,RTK）G蛋白连接受体蛋白连接受体（G protein-Coupled Receptors)细胞因子受体细胞因子受体（Cytokine Receptors）粘附因
10、子受体粘附因子受体（Adhesion Molecules Receptors）酪氨酸激酶受体酪氨酸激酶受体ClassExamplesStructural Features of ClassIEGF receptor,NEU/HER2,HER3cysteine-rich sequencesIIinsulin receptor,IGF-1 receptorcysteine-rich sequences;characterized by disulfide-linked heterotetramersIIIPDGF receptors,c-Kitcontain 5 immunoglobulin-li
11、ke domains;contain the kinase insertIVFGF receptorscontain 3 immunoglobulin-like domains as well as the kinase insert;acidic domainVvascular endothelial cell growth factor(VEGF)receptorcontain 7 immunoglobulin-like domains as well as the kinase insert domainVIhepatocyte growth factor(HGF)and scatter
12、 factor(SC)receptorsheterodimeric like the class II receptors except that one of the two protein subunits is completely extracellular.The HGF receptor is a proto-oncogene that was originally identified as the Met oncogeneVIIneurotrophin receptor family(trkA,trkB,trkC)and NGF receptorcontain no or fe
13、w cysteine-rich domains;NGFR has leucine rich domainG蛋白连接受体蛋白连接受体 G-ProteinNEINSIDEOUTSIDEoutsideinsideG protein-coupled receptorsSchematic diagram of the general structure of G protein linked receptors.All receptors of this type contain seven transmembrane a a-helical regions.The loop between a a h
14、elices 5 and 6,and in some cases the loop between helices 3 and 4,which face the cytosol,are important for interactions with the coupled G protein.olfactory R,adenosine R,cannabinoid R,.Family AFamily BGPCRFamily CFamily DFamily EFamily FGroup IGroup IIGroup IIIGroup VIGroup IVGroup VGroup IGroup II
15、Group IIIGroup IIGroup IVGroup IIIGroup Iserotonin R,adrenergic R,dopamine R,histamine R,muscarinic R,.rhodopsins,endothelin R,thyrotropinreleasing hormone R,.bradykinin R,.angiotensin R,chemokine R,thrombin R,.melatonin R,.calcitonin R,.parathyroid hormone/parathyroid-related-peptide Rglucagon R,gr
16、owth hormone releasinghormone R,pituitary adenylyl cyclaseactivating peptide R,.latrotoxin R,.metabotropic glutamate R,.calcium R,.GABA-B R,.STE2 R,.STE3 R,.cAMP R,.bradykinin R,.G Protein-coupled ReceptorsG Proteinaa ai3a asa aolfa ai1a ai2a aoAa aoBa at1a at2a aga aza aqa a11a a14a a15a a16a a12a
17、a13136080100%amino acid identitya asa aia aqa a12G Protein a a SubunitsGs:linking-adrenergic receptors and adenylyl cyclase Gi:Inhibiting Certain Isotypes of Adenylyl CyclasesEach cytokine/hematopoietic receptor is a composite of structurally distinct protein domains.Members of this receptor family
18、contain one,two,or even three polypeptides.The transmembrane domain consists of a single alpha helix of about 20 amino acids.Ligand binding occurs at a domain near the transmembrane domain 细胞因子受体细胞因子受体 Cytokine ReceptorsLigand binding occurs in a region near the transmembrane domain.The cytosolic do
19、main of a cytokine receptor does not possess intrinsic catalytic activity.Rather,the ligand-bound receptor recruits and activates the cytosolic tyrosine kinase JAK.JAK substrates include JAK itself,the receptor,IRS molecules,and the transcriptional activator STAT.Phosphorylated JAK also interacts wi
20、th other signal transduction proteins through SH2 domains粘附因子受体Adhesion Molecules ReceptorscadherinsintegrinsIg超家族超家族selectin连接蛋白连接蛋白Protein Binding Domain related to signal transduction SH2 domain SH3 domain PH domain Death Domain Src,is the product of the first proto-oncogene to be characterized.S
21、rc,is a non-receptor tyrosine kinaseOther proteins have homologies to Src domainsSH Src-homology regions SH2 and SH3 domains:mediate protein-protein interactions in cellular signaling cascades:very common in proteins outside the Src family.SH2:binds peptides with consensus:(PTyr-Met/Val-X-Met)SH3:-b
22、arrel.Interacts with proline-rich peptide targets The Src homology 2(SH2)domain has been found in a number of signal transduction pathways.Its primary function is to bind phosphotyrosines and in doing so localizing different proteins necessary to transmitt the proper function.SH2 DomainsSH2 DomainsP
23、leckstrin homology domain(PH)Structural overview of DH-PH complexDHPHThe PH domain is able to interact with the DH domainPHSH2SH3pTyrproteinproteinX-P-P-X-PMembraneFunction of AdaptorG蛋白蛋白 经典经典G蛋蛋 小分子量小分子量G蛋白蛋白TYPES OF G-PROTEINSRAS proteins are small G-proteins Cell proliferation Membrane bound GTP
24、-dependent switches Activate MAP kinasesSmall GTP-binding proteins include(roles indicated):w initiation&elongation factors(protein synthesis).w Ras(growth factor signal cascades).w Rab(vesicle targeting and fusion).w Ran(transport of proteins into&out of the nucleus).w Rho(regulation of actin cytos
25、keleton)All GTP-binding proteins differ in conformation depending on whether GDP or GTP is present at their nucleotide binding site.Generally,GTP binding induces the active state.第二信使第二信使胞内激酶胞内激酶 MAPK pathway(Mitogen-activated protein kinase pathway)Erk(extracellular-signal regulated kinase):p44/p22
26、JNK(c-Jun N-terminal kinase);SAPK(stress-activated protein kinase)p38 cAMP-PKA pathway cGMP-PKG pathway DAG-PKC pathway PI-3K pathway Ca2+-CAMK pathway MAP kinase pathwayThe MAP kinase CascadeMAP-kinaseMAP-kinase-kinaseMAP-kinase-kinase-kinasechanges in protein activitychanges in gene expression核受体核
27、受体INACTIVE RECEPTORACTIVE RECEPTOR核受体核受体Tyrosine Kinase Receptors signal pathwayG protein-coupled Receptors pathwayTGF signal pathwayTNF signal pathwayWnt signal pathway主要信号传导通路主要信号传导通路Mechanism of Tyrosine Kinase Receptors When hormone binds to the extracellular domain the receptors aggregate Mecha
28、nism of Tyrosine Kinase Receptors When the receptors aggregate,the tyrosine kinase domains phosphorylate the C terminal tyrosine residues Mechanism of Tyrosine Kinase Receptors This phosphorylation produces binding sites for proteins with SH2 domains.GRB2 is one of these proteins.GRB2,with SOS bound
29、 to it,then binds to the receptor complex.This causes the activation of SOS.Mechanism of Tyrosine Kinase Receptors SOS is a guanyl nucleotide-release protein(GNRP).When this is activated,it causes certain G proteins to release GDP and exchange it for GTP.Ras is one of these proteins.When ras has GTP
30、 bound to it,it becomes active.Mechanism of Tyrosine Kinase Receptors Activated ras then causes the activation of a cellular kinase called raf-1 Mechanism of Tyrosine Kinase Receptors Raf-1 kinase then phosphorylates another cellular kinase called MEK.This cause the activation of MEK Mechanism of Ty
31、rosine Kinase Receptors Activated MEK then phosphorylates another protein kinase called MAPK causing its activation.This series of phosphylating activations is called a kinase cascade.It results in amplification of the signal Mechanism of Tyrosine Kinase Receptors Among the final targets of the kina
32、se cascade are transcriptions factors(fos and jun showed here).Phosphorylation of these proteins causes them to become active and bind to the DNA,causing changes in gene transcription Signal Transduction Through Receptor Tyrosine Kinases The G Protein Activation/Inactivation Cycle cAMP PathwayIP3 Pa
33、thwaySignaling moleculeCell surface receptorG proteinEnzymeTarget proteinIntracellular mediatorcAMPCa+Canonical,SMAD-dependent TGF-signaling pathwayNon-canonical TGF-signaling and crosstalk with other signaling pathwaysDEATH signals TNF-alphaCD95 ligand/Fas ligandDeath receptors,e.g.CD95Death domain
34、sBinding to the receptor induces receptors to cluster and trimerize After binding to ligand,receptors form trimersDeath domainsFADD(Fas associated death domain protein)is recruited via its death domain DED(death effector domain)of FADD recruits pro-caspase 8 via its DED FADD-CASP8 complex brings mul
35、tiple pro-caspase 8 molecules in close proximity(induced proximity aggregation results in their cross-activation).This is the DISC-complex.DISC complexActivated caspase-8(a heterotetramer)is released from DISC into the cytoplasm caspase-8 cleaves pro-apoptotic BID protein.BID interacts with the pro-
36、apoptotic BCL2 relatives BAX and BAKThis amplifies apoptosis induction through the cell-extrinsic pathway Nature Reviews Cancer 2;420-430(2002);TARGETING DEATH AND DECOY RECEPTORS OF THE TUMOUR-NECROSIS FACTOR SUPERFAMILYTNF-a and NF-B cell surface TNF-a receptor NF-B inactive in cytoplasm with IB k
37、inase removes IB NF-B trans-locates to nucleusNF-kappa B is an anti-apoptotic factorVia NF-kappaB TNF blocks its own cell death potential chemotherapy activates NF-kB within tumor cells NF-kB inhibitors augment chemotherapy many common synthetic(e.g.,aspirin),and traditional(e.g.,green tea,curcumin)
38、remedies target,at least in part,the NF-kB signaling pathway The Wnt signaling pathwayIntegrin 传导通路Networks of Signal Transduction600 G protein-coupled receptors+Multiple gene families and combinationsof G protein subunits20Ga a isoforms6 G isoforms12 G isoforms+Multiple gene families for selected e
39、ffector proteinsAdenylyl cyclasesPhospholipasesIon channelsThe phenomenon of crosstalk increases the complexity and variety of signal transduction pathways in a cell.The net result is that a single cellular response may be sensitive to several different extracellular stimuli.Crosstalk is,in part,a r
40、eflection of multiple gene families for all major protein components of signal transduction pathways.The magnitude of amplification within this cellular cascade structure often exceeds 10+4.That is,the binding of one molecule of ligand to a cell-surface receptor leads a change of 10,000-fold in the
41、intracellular concentration of a metabolic product.肿瘤临床中的信号传导肿瘤临床中的信号传导 信号传导异常与肿瘤发生信号传导异常与肿瘤发生 肿瘤治疗肿瘤治疗增殖失控：增殖失控：生长因子：c-Sis生长因子受体:HER-2 蛋白激酶:c-SrcG蛋白:c-Ras细胞周期调控因子:Rb凋亡受阻凋亡受阻TNFFas/FasLBcl/Baxp53侵袭与转移侵袭与转移IntegrinE-CadherinVEGF信号传导异常与肿瘤发生信号传导异常与肿瘤发生肿瘤发生与发展是多因素作用、多基因参与、经过多个阶段形成。肿瘤发生与发展是多因素作用、多基因参与、经过
42、多个阶段形成。肿肿瘤瘤中中常常见见的的信信号号传传导导异异常常Familial adenomatosis polyposis coli（FAP,APC)Deleted in colorectal carcinoma(DCC)Based on genetic analysis,at least two pathways are characterized in detail,which lead to colon cancer development.One pathway(indicated with red arrows)initiates with mutations in the APC
43、 gene followed by mutations in K-ras,deleted in colorectal cancer(DCC)and p53 genes.The second pathway(indicated with blue arrows)is initiated by mutations in the MMR genes(hMSH3,hMSH)and other genes(TGFbetaIIR,IGFIIR,PTEN,BLM,Tcf-4,Bax and E2F4).Beside these there are many other less characterized
44、pathways with a high degree of overlapping among them.At least,seven gene mutations are needed to develop a normal epithelial cell into carcinoma.Frontiers in Bioscience 10,1118-1134,May 1,2005Model for genetic alterations in the development of colorectal cancerAdaptorGRFs12,13,61,63mutationGTPaseGT
45、P结合活性半衰期延长3-9倍结肠癌、胰腺癌等 突变的ras降低了Ras蛋白水解GTP为GDP的能力。降低了自身内源的GTPase的活性，导致Ras与GTP持续结合具有促进细胞增长的作用。G TArg Valcolorectal carcinomas 30-60%,K-rasnon-melanoma skin cancer 30-50%,H-ras hematopoietic neoplasia of myeloid origin 18-30%,K-and N-rasSeminoma 25-40%,K-ras In other tumors,a mutant ras gene is found
46、at a lower frequency:for example,in breast carcinoma(0-12%,K-ras),Neuroblastoma(0-10%,K-and N-ras)Wnt-1 was found as an oncogene activated by the Mouse Mammary Tumor Virus in murine breast cancer.APC was first isolated as a tumor suppressor gene in human colon cancer.After establishing that APC and
47、beta-catenin bind to each other activating mutations in the human beta-catenin gene were found in human colon cancer and melanomas.These mutations alter specific beta-catenin residues important for GSK3 phosphorylation and stability.The role for Frat/GBP in cancer is illustrated by its activation by
48、 proviral insertion in mouse lymphomas.A recent example of the link between cancer and Wnt signaling comes from the identification of the Drosophila gene legless as a homolog of Bcl-9 a gene implicated in B cell malignancies.Interestingly,mutations in the human AXIN1 gene were reported in human hepa
49、tocellular carcinomas.TCF1 can also act as a tumor suppressor gene,as Tcf1 mutant mice develop adenomas in the gut and mammary glands Several components of the Wnt signaling pathway have been implicated in human tumors or experimental cancer models.EMT:epithelial-mesenchymal transition肿瘤的转移及EMT（Epit
50、helial-Mesenchymal Transition）Different types of EMTJ.Clin.Invest.119:14201428(2009).doi:10.1172/JCI39104Contribution of EMT to cancer progressionBiphasic activities of the TGF-signaling pathway during tumorigenesis:from the tumour suppressor to the tumour promoter肿瘤治疗肿瘤治疗肿瘤治疗肿瘤治疗 单克隆抗体单克隆抗体Hercepti
