信号分子与信号转导signalingtransduction 02 ppt课件

Classification of phosphatase according to the Amino acid sequence in active center Ser/Thr phosphatase Tyr phosphatase Dual specificity . G protein/small G protein guanine nucleotide binding protein，G protein（鸟苷酸结合蛋白）亦称GTP结 合蛋白 a signal molecule in various pathways, functioning differently in different cells Two forms of G protein G protein binding with GTP: its active form GTP hydrolysed to GDP: inactive form 2 types of G protein ： Hetero-trimer G protein:（G）,(G) binding with receptor with 7 transmembrane dormains， Small G protein (21kD） 1. Hetero-trimer G protein mediated receptor signal directly G G Multiple Sites subunit with GTPase act. Binding site with receptor Bingding site withsubunits GDP/GTP binding site Binding with dwonstream molecules formed a complex with G,localized in regulate targeted protein directlyin mammalian The activation/deactivation cycle for hormonally stimulated adenylate cyclase G protein-coupled receptors，GPCRs Ligand- GPCRs G protein-（ AC,PLC)-cell function The role of PIP2 in intracellular signaling 2. Ras surperfamily: important signal molecules Small G protein （21kD），functioning as switch Ras is a first discoved G protein Ras family: each contains a GTPase domain Factors control small G protein act. Factor increasing act. ： guanine nucleotide exchange factor (GEF) guanine nucleotide release protein (GNRP) Factor decreasing act.： guanine nucleotide dissociation inhibitor (GDI) GTPase activation protein (GAP) Ras activation and its regulators GTP GDP Ras Ras SOS GAP on off Summary of Section 3 1. Proteins are the main components of signaling pathways 2. Proetin kinases and phosphotases are the switch in signaling pathways. 3. G protein and small G protein are function as their binding with GTP/GDP Section 4 The Structural Basis of Signal Transduction Network 细胞信号转导网络的结构 基础 . Signaling Complex and its character Proteins wont separated each other in cells but aggregated Protein complex-functioning in life 1. Signaling complex ensures the efficiency, precision, variety Priority: directly contact，efficency, precision amplification collaboration, variety complex, multiple 2. Signaling complex exists at membrane and cytoskeleton structure Protein complex existed in membrane structure or cell skeleton compartmentation。 Advantage 由于已经有相对固定的分子作为集合目标 存在，有利于信号转导分子很快找到结合 伴侣，因此复合体转导效率要高于一个完 全自由扩散的系统； 在形成信号转导复合体时，转导分子将以 有序的方式依次进入复合体，因此信号转 导的准确性会高于自由扩散系统。 3. Components of complex changes depended on exogenous signals Dynamic state: the components and formation of signal complex depended on exogenous signals Significance: withdrew ligand - stop signaing immediately reutilization of signal molecules, save energy . Domain is substantial basis of protein-protein interaction protein interaction domain 1. prot-prot interaction mediated by domains Character of protein interaction domain (PID) one molecule contains two PID same domain existed in various proteins, but sequence are not exactly same binding specificity PID doesnt have enzyme activity, just binding Distribution and role of protein interaction domain Protein kinase Btk PHTH SH3 SH2 催化区 Adaptor Grb2SH3 SH2 SH3 TF stat DNA 结合区 SH2TA Cytoskeleton tensin / SH2PTB PID recognized motif Src homology 2 SH2Tyr-Pi Src homology 3 SH3Pro rich pleckstrin homologyPHPhospholipid derivation Protein tyrosine binding PTBTyr-Pi WW WWPro rich Domain and its recognized motif 2. Src homology 2 (SH2) domain Src homology 2 domain: SH2 domian Function: the recognized motif is phosphorylated tyrosine and neighboring amino acids Different protein contains different SH2 - selectivity 3. SH3 Domain Src homology 2 domain: SH3 domian Function: the recognized motif is proline- rich (9-10 Pro) sequence 4. PH Domain recognizes the phospholipids PH domain in pleckstrin in platelet，so called pleckstrin homology PH binding with membrane PL derivative ，make its localization to membrane, enzyme activity increase PH is a basic structure of prot-prot, prot- lipid interaction . adaptor proteins and scaffolding proteins adaptor protein a kind of mediator protein, Link one, upstream prot., to another, downstream role：recruit and organize the complex Most adaptor proteins contain two domains, no other special domain 1. adaptor protein Adaptor protein Nck SH2 C N SH3 SH3SH3 HGFR, VEGFR, BCR-Abl PDGFR, EphB1 SLP-76, HPK1, p130cas IRS-1,p62doc CKIg2,WASP,IRS-1, DOCK180, NIK IRS-1,DOCK180, Sos, NIK,Pak1,Pak3,NAP4,WIP, dynamin, synaptojanin、 Abl,c-Cbl Abl,c-Cbl,NAP1,Sam68 2. Scaffolding proteins ensures the efficiency and specificity Scaffolding proteins: large MW, binding with many signal molecules in same pathway Significance keep the related molecules gather together, keep specificity, not across to with other pathway Scaffolding proteins increase or decrease the activity of signaling create the complex and variety in signaling pathway Sumaary of Section 4 1. Signaling complex exists at membrane and cytoskeleton structure. Within complex the special domain in a protein is a base of interacting with others. 1. Adaptor proteins and scaffolding proteins are the linker molecules in signaling and network. Section 5 General Signal Pathways Mediated by Membrane Receptors 膜受体介导的基本信号转导通路 3 types of membrane bound receptor ： Ion channel receptor (ICR) G-protein coupling receptor (GPCR) Single transmembrane receptor (STMR) ICR GPCRSTMR 内源 性配 体 神经递 质 神经递质 、激素、趋化 因子、外源刺激（味，光 ） 生长因子 细胞因子 结构寡聚体 形成的 孔道 单体具有或不具有催 化活性的单体 跨膜 区段 数目 4个7个1个 功能离子通 道 激活G蛋白激活蛋白酪氨酸 激酶 细胞 应答 去极化 与超极 化 去极化与超极化调节蛋 白质功能和表达水平 调节蛋白质的功 能和表达水平， 调节细 胞分化和 增殖 Characters of 3 types receptors . Ion Channel Receptor structurally a channel, open or close pass through ion, ligand-gated receptor channel Ligand: neurotransmitter mainly Acetyl choline receptor Acetylcholine Binding Site Ion channel overlook side look The role of Acetylcholin Ion channel memb. electric potential change chemical signal formation cell function Ion channel Cation channel: Acetyl Choline, Glutamic acid, 5-Hydroxytrypotamine Anion channel: Glycine， -aminobutylic acid . G-protein coupling receptor second messenger-target molecules GPCR: binding G protein with tri-subunit activate G protein GPCR a serpentine receptor, 7 transmembrane G蛋白偶联区 1. G-protein activation initiates signaling Model of transduction via G-protein ： ligand receptor binding receptor activates G-protein G-protein act. or inh. target prtoein change second messenger level or distribution, second messenger affects its target molecule conformational change G-protein cycle 2. Activated G-protein alters activity of target mole. 活化的G蛋白的亚基主要作用于生成或水 解细胞内第二信使的酶，如AC、PLC等效 应分子（effector），改变它们的活性，从 而改变细胞内第二信使的浓度。 可以激活AC的G蛋白的亚基称为s（s 代表stimulate）；反之，称为i（i代表 inhibit）。 G Effective mole. Messenge in cyto. Target mole. asAC cAMPPKA aiAC cAMPPKA aqPLC Ca2+、IP3、 DAG PKC atcGMP-PDE cGMPNa+ Chan. Ga subunit and its effect 3. Glucagon receptor - AC-cAMP-PKA pathways Adrenocorticotrophin (ACTH) Melanotrophin (MSH) Corticoliberin (CRH) Olfaction molecule Dopamine Parathyrin AdrenalineProstaglandin E1, E2 Glucagon 5-HT（1a）、5-HT（2 ） Histamine （H2 receptor ） Somatostadin Lutropin (LH)Taste molecule Signals acts by AC-cAMP-PKA pathways 4. Angiotensin II receptor - PLC-IP3/DAG- PKC Angiotensin II receptor is a GCPR q PLC-IP3/DAG-PKC pathway Acetyl Choline M1 light ( fruit fly )5-HT（1c） ATP Gastrin releasing peptide Thyrotropin releasing hormone (TRH) Adrenergic agonist Glutamine vasopressin- antidiuretic hormone Angiotensin II gonadotrophin releasaing hormone (GRH) histamine H1 receptor Signals acts by PLC-IP3/DG-PKC 此外，由于G蛋白亚型的不同，形成多 种其他通路和效应，如PDE-cGMP-Na+ 通道信号转导通路、PLC-IP3-Ca2+/CaM -PK信号转导通路等。 . Enzyme coupling receptor-protein kinase kinase protein kinase target mole 酶偶联受体指那些自身具有酶活性，或 者自身没有酶活性，但与酶分子结合存 在的一类受体。 这些受体大多为只有1个跨膜区段的糖 蛋白，亦称为单跨膜受体。 酶偶联受体种类繁多，但是以具有PTK 活性和与PTK偶联的受体居多。 常见的酶偶联受体： 受体型蛋白酪氨酸激酶（receptors tyrosine kinases， RTKs） 蛋白酪氨酸激酶偶联受体（tyrosine kinase-coupled receptors，TKCRs） 受体型蛋白酪氨酸磷酸酶（receptors tyrosine phosphatases，RTPs） 受体型蛋白丝/苏氨酸激酶（receptors serine/threonine kinase，RSTK） 受体型鸟苷酸环化酶（receptors guanylate cyclases， RGCs） 酶偶联受体大部分是生长因子和细胞因子 的受体，它们所介导的信号转导通路主要 是那些调节蛋白质的功能和表达水平、调 节细胞增殖和分化。 1. PTK coupling receptor : similar model PTK coupling receptor主要通过蛋白 质相互作用激活自身或细胞内其他的 PTK或丝/苏氨酸激酶来转导信号。 PTK偶联受体介导的信号转导途径的 基本模式 ： 结合配体后受体形成二聚体或寡聚体； 第一个蛋白激酶被激活。对于具有蛋白激酶活性的受体来说， 此步骤是激活受体胞内结构域的蛋白激酶活性；对于没有蛋白 激酶活性的受体来说，此步骤是受体通过蛋白质-蛋白质相互作 用激活与它紧密偶联的蛋白激酶； 通过蛋白质-蛋白质相互作用或蛋白激酶的磷酸化修饰激活下游 信号转导分子，通常是继续活化下游的一些蛋白激酶； 蛋白激酶通过磷酸化修饰激活代谢途径中的关键酶、反式作用 因子等，影响代谢途径、基因表达、细胞运动、细胞增殖等。 表皮生长因子受体作用机制： 2. EGFR signaling pathway : RasMAPK 表皮生长因子受体（epidermal growth factor receptor, EGFR）是一个典型的受 体型PTK。 RasMAPK途径是EGFR的主要信号通 路之一。 EGFR介导的信号转导过程 3. Others pathways than enzyme couping receptor T细胞抗原受体、B细胞抗原受体、肥大细 胞表面的IgE受体 属于酶偶联受体，它们自身不具备蛋白酪氨酸激 酶活性； 非受体型的Src家族蛋白酪氨酸激酶和ZAP70家族 蛋白酪氨酸激酶是这一类受体的直接信号转导分 子。 下游分子包括PLC、MAPK家族的活化，并有 多种衔接蛋白参与。 大部分白细胞介素（interlukin, IL）受体 属于酶偶联受体。 通过JAK（Janus Kinase）-STAT（signal transducer and activator of transcription）通路转导信号。 细胞内有数种JAK和数种STAT的亚型存在，分别转 导不同的白细胞介素的信号。 白介素介导的信号转