受体酪氨酸激酶调节钾离子通道功能的研究进展

受体酪氨酸激酶是一个具有内在酪氨酸蛋白激酶活性的膜受体超家族,成员众多,信号转导通路复杂多样.受体酪氨酸激酶激活后,既可以通过磷酸化其下游信号分子,影响基因转录和表达的过程,从而在细胞生长、增殖、分化和代谢方面起重要的调节作用;也可以通过活化下游分子对细胞功能进行快速调节包括对离子通道功能的调节.钾离子通道具有稳定细胞膜电位和调节细胞兴奋性的重要作用.本文主要就受体酪氨酸激酶对钾离子通道功能快速调节及目前的研究进展进行综述.     

Influence of berberine on protein tyrosine kinase of erythrocyte insulin receptors from type 2 diabetes mellitus

Objective： Bererine has been used to treat type 2 diabetes mellitus in Chinese traditional medicine because of its hypoglycemic effect. In this report, we compared the intrinsic tyrosine kinase activities of erythrocyte insulin receptors from type 2 diabetes mellitus with or without stimulation by berberine in vitro. Methods- Preparations containing insulin receptors were obtained from soluble human erythrocytes, and the insulin receptors were partially purified by affinity chromatography. The tyrosine kinase activity was measured by the exogenous substrate phosphorylation. Results： Both the membrane tyrosine kinase activity and the purified receptor tyrosine kinase activity from diabetics decreased significantly compared with those of normal individuals （reduced by 67.4% and 47.2%, respectively）. After incubation with berbefine, there is a statistical difference in the activity of membrane tyrosine kinase for diabetic patients （ a 150% increase）. Berefine had no effect on the tyrosine kinase activity of purified insulin receptors. Conclusion： We concluded from these results that berbefine was able to improve the insulin sensitivity by increasing the protein tyrosine kinase activity of membrane-bound insulin receptors from type 2 diabetes mellitus.     

胆碱能受体和肾上腺素能受体磷酸化的调节作用机制研究

目的：研究受体激活剂或抑制剂影响G蛋白偶联受体激酶2（GRK2）介导的胆碱能m2受体和β2肾上腺素能受体膜蛋白（β2-AR）磷酸化的调节机制。探讨兴奋剂使m2受体和β2-AR受体活化,引发受体磷酸化级联反应,进而影响蛋白激酶催化受体磷酸化的起始机制。方法：制备亲和层析柱;利用亲和层析方法从大鼠脑中纯化毒草碱乙酰胆碱m2受体;分别将纯化的毒蕈碱乙酰胆碱m2受体或β-肾上腺素受体,G蛋白偶联受体激酶-2,[γ-P^32]ATP与受体激活剂或抑制剂共同保温,聚丙烯酰胺凝胶电泳分离蛋白,放射性自显影检测m2受体磷酸化结果。结果：m2受体激活剂氨甲酰胆碱明显增强m2受体的磷酸化,而m2受体抑制剂阿托品或肝素（GRK2抑制剂）完全阻断了m2受体的磷酸化。m2受体的磷酸化是依赖激活剂如氨甲酰胆碱作用发生的,呈明显的剂量依赖关系;β2-AR的激活剂特布他林增强肾上腺素能受体的磷酸化,而肝素可完全阻断β2-AR的磷酸化;并且证实氨甲酰胆碱对mAChR2,特布他林对β2-AR磷酸化的增强作用是选择性的作用结果;HEL299细胞磷酸化实验结果也显示氨甲酰胆碱可以增强HEL299细胞m2受体的磷酸化,阿托品可以抑制HEL299细胞m2受体的磷酸化。结论：实验证实氨甲酰胆碱、特布他林和阿托品等一些m2受体和β2-AR的激活剂及抑制剂对M2受体和β2-AR磷酸化的调节作用。提示激活剂增强m2受体和β2-AR的磷酸化可能是这些受体活化一个重要部分,由此开始加速受体敏感性下调,受体耐受性增强。     

Tumor necrosis factor (TNF) superfamily ligands and receptors

1　TNF ligand and receptor superfamily membersTumor Necrosis Factor (TNF) supergene family and its cognate family of rel ated r eceptors (TNF-R) have expanded in the past few years to include at least 17 lig ands and 22 receptors (The New TNF Nomenclature Scheme, http://www.gene.ucl.ac.uk/users/nomenclature/genefamily/tnfinfo.html)[1]. With the exception of LTα,whichlacks a hydro phobic transmembrane region, allof the ligands are type Ⅱintegral membrane pro teins that may also function as soluble proteins. Many of the TNF superfamily ligands pair with a single, although some specific receptor, including TNFα, LT α, TRAIL, FasL, LIGHT and TRANCE/RANKL, bind to multiple receptors (Tab 1).     

以c-Met为肿瘤治疗靶点的受体酪氨酸激酶抑制剂的研究进展

受体酪氨酸激酶c-Met在细胞的增殖、代谢以及肿瘤的产生、转移、血管生成中扮演着重要角色,c-Met成为抗肿瘤治疗的重要靶点。HGF/c-Met信号通路与VEGFR等其他通路的相互作用(cross-talk)影响了抗肿瘤药物的作用效果,产生耐药性,因此,多激酶靶点联合用药成为新的抗肿瘤治疗手段。本文介绍了c-Met信号通路与多种膜受体间的相互作用以及由这种相互作用引起的对激酶抑制剂的耐药性,并综述了单靶点和多靶点的小分子c-Met抑制剂的研究进展。     

M受体-G蛋白信号转导途径研究进展

毒蕈碱乙酰胆碱受体（mAChR）是G蛋白偶联受体超家族中的一员，具有该家族特征性的结构和信号转导方式。GTP结合蛋白（G protein）是一类具有GTP酶活性的蛋白质，由α、β和γ三个亚基构成。mAChR可以与G蛋白偶联，引起GTP与α亚基结合，导致Gα与Gβγ分离。近年来发现，不但Gα-GTP可以调节效应分子，Gβγ也可以调节许多效应分子如腺苷酸环化酶、磷脂酶C、K⁺通道、Ca²⁺通道、MAPK和受体激酶等，介导一系列的生物学效应，在信号转导过程中发挥重要的作用。     

PD-1/PD-L1信号通路在多系统疾病中的研究进展

PD-1属于免疫球蛋白超家族成员,其以单体形式存在于细胞表面,通常与配体结合后,ITSM区的酪氨酸发生磷酸化,蛋白酪氨酸磷酸酶分子则被招募使下游的效应分子去磷酸化,转导负性信号,从而发挥负性调节作用,抑制T细胞的增殖和细胞因子的产生.在正常情况下,PD-1/PD-L1信号通路可以诱导和维持外周组织的免疫耐受,对防止组织的过度炎症反应以及自身免疫性疾病的发生具有积极作用,而在不正常的情况下,如血液系统疾病、免疫系统疾病和心血管系统疾病时,此信号通路也发挥着重要的调节作用.     

白细胞介素-7诱发皮肤T细胞淋巴瘤细胞JAK-3的磷酸化和活化

目的：ＩＬ７可刺激一些良性和恶性淋巴细胞增生,其中包括来自皮肤样Ｔ细胞瘤（ＣＴＣＬ）病人的肿瘤细胞。Ｊａｎｕｓ激酶家族（ＪＡＫｓ）与许多细胞因子受体的信号传导系统有关。ＪＡＫ３是ＪＡＫｓ激酶家族的新成员,其在自然杀伤细胞（ＮＫ）和活化的Ｔ细胞上表达,并在这些细胞中从功能上和物理上与白细胞介素２受体（ＩＬ２Ｒ）结合起来。为此,本研究进一步探讨白细胞介素７（ＩＬ７）引起皮肤样Ｔ细胞瘤肿瘤细胞ＪＡＫ３的磷酸化和活化。方法：ＣＴＣＬ外周血中分离的肿瘤细胞,用ＩＬ７分别处理１、５、１０、２０ｍｉｎ,蛋白裂解物用抗ＪＡＫ３抗体,抗ｐ５９ｆｙｎ抗体进行免疫沉淀,用抗ＪＡＫ３和抗磷酸化酪氨酸作Ｗｅｓｔｅｒｎ印迹检测。结果：ＩＬ７能引起ＣＴＣＬ肿瘤细胞的ＪＡＫ３酪氨酸磷酸化,抗ｐ５９ｆｙｎ抗体能结合ＪＡＫ３,未发现ＩＬ１２能诱导ＣＴＣＬ细胞的ＪＡＫ３磷酸化。结论：提示ＩＬ７可能在ＣＴＣＬ的病理生理学上起一定的作用,且证实在ＣＴＣＬ细胞中ＩＬ７受体介导了酪氨酸磷酸化的信号传导途径。     

膜联蛋白Ⅰ的结构和生物学功能

膜联蛋白Ⅰ(ANNX-Ⅰ)是一种钙依赖的磷脂结合蛋白,是Annexins超家族中第一个被发现的成员。ANNX-Ⅰ作为表皮生长因子受体激酶和蛋白酶C的磷酸化底物-磷酯酶A2的抑制物,具有多种生物学功能,包括囊泡运输、胞吐作用的膜融合、信号转导和钙离子通道的形成、调控炎性反应、细胞分化和细胞骨架蛋白间的相互作用等。本文就ANNX-Ⅰ的结构组成,在细胞生长、分化、凋亡、信号转导、炎性反应等方面的生物学功能及其表达与肿瘤疾病的关系和作用作简要综述。     

NNRG/ErbB信号通路在神经系统中的研究进展

神经调节蛋白(NRG)是一类细胞间信号转导蛋白,其功能性受体是由ErbB酪氨酸激酶受体组成,属于跨膜酪氨酸激酶的表皮生长因子受体家族成员,包括表皮生长因子受体(也称ErbB1)、ErbB2/人源的ErbB2/neu、ErbB3/HER3和ErbB4/HER4。NRG通过诱导ErbB受体构象变化,使ErbB蛋白形成二聚体,继而激活酪氨酸激酶,引起C-末端的自身酪氨酸磷酸化和反式酪氨酸磷酸化,引起下游信号通路转导从而发挥其生物学作用。     

PPAR-γ激活剂对脂联素及脂联素受体的影响

过氧化物酶体增殖物激活受体(PPAR-γ)是核受体超家族成员之一,通过PPAR-γ激活剂特异激活,促进脂肪细胞分化,增加胰岛素敏感性,在胰岛素抵抗、动脉粥样硬化、糖尿病等代谢性疾病的发生、发展及防治过程中扮演重要角色。脂联素是脂肪细胞分泌的一种细胞因子,通过结合脂联素受体——AdipoR1和AdipoR2发挥抗炎、抗糖尿病、抗动脉粥样硬化的作用。PPAR-γ激活剂在动物以及人体中可均增加脂联素的水平,并对脂联素复合物、脂联素受体产生影响。通过对PPAR-γ激活剂对脂联素以及脂联素受体可能作用机制的阐述,对于糖尿病和动脉粥样硬化的治疗具有积极的临床意义。     

Role of tyrosine kinase signaling for beta-cell replication and survival

Diabetes mellitus is commonly considered as a disease of a scant beta-cell mass that fails to respond adequately to the functional demand. Tyrosine kinases may play a role for beta-cell replication, differentiation (neoformation) and survival. Transfection of beta-cells with DNA constructs coding for tyrosine kinase receptors yields a ligand-dependent increase of DNA synthesis in beta-cells. A PCR-based technique was adopted to assess the repertoire of tyrosine kinases expressed in fetal islet-like structures, adult islets or RINm5F cells. Several tyrosine kinase receptors, such as the VEGFR-2 (vascular endothelial growth factor receptor 2) and c-Kit, were found to be present in pancreatic duct cells. Because ducts are thought to harbor beta-cell precursor cells, these receptors may play a role for the neoformation of beta-cells. The Src-like tyrosine kinase mouse Gtk (previously named Bsk/Iyk) is expressed in islet cells, and was found to inhibit cell proliferation. Furthermore, it conferred decreased viability in response to cytokine exposure. Shb is a Src homology 2 domain adaptor protein which participates in tyrosine kinase signaling. Transgenic mice overexpressing Shb in beta-cells exhibit an increase in the neonatal beta-cell mass, an improved glucose homeostasis, but also decreased survival in response to cytokines and streptozotocin. It is concluded that tyrosine kinase signaling may generate multiple responses in beta-cells, involving proliferation, survival and differentiation.     

血管紧张素Ⅱ对大鼠肝星状细胞收缩及Rho-Rock通路的影响

目的 探讨血管紧张素Ⅱ(AngⅡ)对大鼠肝星状细胞(HSC)ROCk通路的影响机制.方法 采用HSC-T6细胞株,给予AngⅡμmol/L处理,聚硅酮膜法直观检测HSC的收缩性;另予AngⅡ 10 μmol/L处理,免疫印迹法检测肌球蛋白轻链(MLC)磷酸化的表达水平.观察AngⅡ 1型受体(AT-1受体)阻断剂伊贝沙坦和Rho激酶特异性抑制剂Y27632对磷酸化MLC表达水平的影响;逆转录聚合酶链反应检测Rock通路Rock2(Rho kinase 2)mRNA的表达.结果 AngⅡ可诱导磷酸化MLC蛋白水平的变化,并呈时间依赖性,15min达到峰值后逐渐减低.伊贝沙坦和Y27632处理组可抑制AngⅡ诱导的MLC蛋白磷酸化水平.AngⅡ处理组Rock2 mRNA的表达显著增强,伊贝沙坦和Y27632均可抑制Rock2 mRNA的表达.结论 AngⅡ可以通过Rock通路来诱导HSC的收缩.     

NR4A孤儿核受体亚家族在代谢综合征中的作用

核受体家族是一组能在生物体内调控发育、代谢、炎症、免疫等多种生物作用的转录因子,而孤儿核受体则是指一群非配体依赖或未知配体的核受体,其中包括NR4A孤儿核受体亚家族。NR4A孤儿核受体亚家族由高度同源的3种受体:Nur77(NR4A1)、Nurr1(NR4A2)和NOR1(NR4A3)组成,他们可被环境中的刺激信号快速诱导,作为非配体依赖的转录因子和早期反应基因行使功能。最近的研究表明,NR4A受体亚家族成员在代谢综合征的各个组分,包括糖代谢异常、脂代谢异常、胰岛素抵抗等方面发挥重要作用。     

Effects of insulin receptor tyrosine protein kinase on insulin resistance after scalding in rats

Ｅｆｆｅｃｔｓｏｆｉｎｓｕｌｉｎｒｅｃｅｐｔｏｒｔｙｒｏｓｉｎｅｐｒｏｔｅｉｎｋｉｎａｓｅｏｎｉｎｓｕｌｉｎｒｅｓｉｓｔａｎｃｅａｆｔｅｒｓｃａｌｄｉｎｇｉｎｒａｔｓ￥（毛旭虎）（许霖水）ＭａｏＸｕｈｕ，ＸｕＬｉｎｓｈｕｉ（ＤｅｐａｒｔｍｅｎｔｏｆＢ...     

Role of Tyrosine Kinase Signaling for β-Cell Replication and Survival

Abstract

Diabetes mellitus is commonly considered as a disease of a scant β-cell mass that fails to respond adequately to the functional demand. Tyrosine kinases may play a role for β-cell replication, differentiation (neoformation) and survival. Transfection of β-cells with DNA constructs coding for tyrosine kinase receptors yields a ligand-dependent increase of DNA synthesis in β-cells. A PCR-based technique was adopted to assess the repertoire of tyrosine kinases expressed in fetal islet-like structures, adult islets or RINm5F cells. Several tyrosine kinase receptors, such as the VEGFR-2 (vascular endothelial growth factor receptor 2) and c-Kit, were found to be present in pancreatic duct cells. Because ducts are thought to harbor β-cell precursor cells, these receptors may play a role for the neoformation of β-cells. The Src-like tyrosine kinase mouse Gtk (previously named Bsk/Iyk) is expressed in islet cells, and was found to inhibit cell proliferation. Furthermore, it conferred decreased viability in response to cytokine exposure. Shb is a Src homology 2 domain adaptor protein which participates in tyrosine kinase signaling. Transgenic mice overexpressing Shb in β-cells exhibit an increase in the neonatal β-cell mass, an improved glucose homeostasis, but also decreased survival in response to cytokines and streptozotocin. It is concluded that tyrosine kinase signaling may generate multiple responses in β-cells, involving proliferation, survival and differentiation.     

神经生长因子对眼科疾病治疗的展望

神经生长因子( nerve growth factor,NGF)是神经营养因子的一种,广泛存在于神经组织和周围靶组织。在中枢神经系统,NGF兼有神经营养和促进神经突起生长的效应,从而参与神经细胞的分化、发育和损伤修复过程。近些年的研究表明,视神经节细胞表达包括NGF在内的多种神经营养因子,表达的NGF通过结合于其受体发挥作用,其高亲和力受体(酪氨酸蛋白激酶A受体) 存在于视神经节细胞上,而其低亲和力受体(p75NTR)则在胶质细胞中广泛表达,这些研究提示NGF可能在眼科疾病的治疗中发挥作用,本文就神经生长因子及其受体在眼组织中的表达、对视神经和视网膜损伤的保护、角膜损伤修复以及对青光眼干眼病的治疗进行了阐述。     

新生小牛肝组织胰岛素受体的功能

检测7例胎龄276～284d、年龄7～11h的新生小牛肝组织胰岛素受体功能。用WGA－Setherose亲和层析法提纯肝组织胰岛素受体（Ins-R），观察受体125I-胰岛素特异性结合率;用Scatchard模型分析Ins－R数目及亲和性；以γ32P－ATP示踪底物多聚Glu4：Tyr1的磷酸化程度，了解胰岛素受体酪氨酸蛋白激酶（TPK）活性。同时检测血糖、皮质醇、胰高血糖素及胰岛素浓度，并分析各变量间的相关性。结果提示：肝组织Ins-R的TPK活性与年龄、胰岛素水平及胰岛素特异性结合率成正相关；新生小牛出生后不久肝组织Ins-R就具有一定的功能，且随着年龄增大而增强。     

A survey shows Beijing has 295 000 overweight kids

Background Angiotensin Ⅱ （AngⅡ） and platelet-derived growth factor （PDGF）-BB can induce hypertrophy in the cultured rat cardiomyocytes through different signal transduction pathways. Angll stimulates growth through G protein coupled receptor （GPCR）, while PDGF-BB acts via receptor tyrosine kinase （RTK）. Although there has been much development on the individual Angll and PDGF-BB mediated signal pathways, little is known about the interactions between these two factors. Therefore, the crosstalk between Angll and PDGF-BB mediated signal pathways in the rat cardiomyocytes was investigated in this study.
Methods Primary culture of neonatal rat ventricular myocytes was prepared. The amount of tyrosine-phosphorylated and non-phosphorylated PDGF-β receptor, Goq/11, and phospholipase C （PLC） β3 were measured by immunoblotting analysis. The statistical analysis was done by one-way ANOVA.
Results Tyrosine-phosphorylated PDGF-β receptor was increased by 120.60% at 1 minute and recovered to the control level at 10 minutes after Angll stimulation. Phosphorylation of PDGF-β receptor triggered by Angll was blocked by Iosartan, a specific antagonist of AT1 receptor. PLC inhibitor U73122, protein kinase C （PKC） inhibitor staurosporine （STS） and mitogen-activated ERK activating kinase （MEK） inhibitor PD98059 also inhibited the Angll-induced phosphorylation of PDGF-β receptor. PDGF-BB slightly increased the expression of Gao/11 protein.
Conclusion Angll transactivates PDGF-β receptor via AT1 receptor-Gaq/11-PLC-PKC pathway in the rat cardiomyocytes. ERK also participates in the transactivation of PDGF-β receptor triggered by Angll.