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G蛋白偶联受体二聚化研究进展 总被引:1,自引:0,他引:1
G蛋白偶联受体是细胞膜受体最大的家族,参与调节多种生理过程,在信号识别及转导中具有重要作用,传统观点认为G蛋白偶联受体作为单体起作用,近年来,越来越多的证据表明,G蛋白偶联受体不仅能以二聚体形式存在,而且在细胞信号转导中起重要作用,尤其是对阿片受体异源二聚体的研究,推动了这一领域的研究。本文综述了G蛋白偶联受体二聚化研究进展,以及同源和异源二聚体的结构与功能。 相似文献
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昆虫多巴胺及其受体的研究进展 总被引:1,自引:0,他引:1
多巴胺(dopamine, DA)是脊椎动物和无脊椎动物体内一种重要的生物胺, 其参与调控了昆虫的多种生理反应和行为过程, 如学习与记忆、 认知、 性取向、 抉择、 运动以及型变等。多巴胺主要通过结合特异性的G蛋白偶联受体, 即多巴胺受体(dopamine receptors, DARs)来发挥生理作用。本文综述了多巴胺在昆虫中的调控、 分布及所参与的生理功能, 如多巴胺调控昆虫的交配、 发育、 嗅觉以及运动行为等, 特别对DARs的信号转导、 生理功能以及药理学等方面进行了详细评述。昆虫的DARs大致可分为两大类: D1-like DARs和D2-like DARs。D1-like DARs包含有2种亚型, 分别为DOP1和DOP2。DOP1仅能偶联胞内cAMP的上升, 而DOP2不仅可以起胞内cAMP的上升, 还可偶联胞内Ca2+的释放。 D2-like DARs仅包含有1种亚型DOP3, 其被激活后引起胞内cAMP的降低。DA通过激活不同的DARs可偶联不同的第二信使系统, 所产生的下游细胞反应则与昆虫的各种行为相关, 而对昆虫DARs的药理学研究将有助于我们开发特异性的杀虫剂用于害虫防治。 相似文献
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目的观测G蛋白偶联受体激酶5(G protein-coupled receptor kinase,GRK5)在帕金森病α-synuclein转基因小鼠模型中的表达变化情况,了解GRK5在帕金森病中的可能作用,为发现帕金森病发病机制和探索更好的治疗方法提供新的方向。方法采用Western blotting和实时荧光定量PCR技术对具有不同的人alpha synuclein(hα--syn)表达水平的帕金森病α-synuclein转基因模型小鼠以及3月龄,6月龄以及9月龄A53T突变型帕金森病α-synuclein转基因模型小鼠脑组织进行GRK5的RNA和蛋白水平检测,与同窝阴性对照小鼠进行比较。结果各组帕金森病α-synuclein转基因小鼠与阴性对照小鼠相比,GRK5蛋白表达水平均有不同程度的增加,并且随着转入的hα--syn蛋白表达水平的高低而有所变化。3月龄和6月龄帕金森病转基因模型小鼠与同月龄阴性对照组小鼠相比,GRK5的mRNA和蛋白水平没有变化;而9月龄帕金森病转基因模型小鼠与同月龄阴性对照组小鼠相比,GRK5的mRNA和蛋白水平都有所增加。结论帕金森病α-synuclein转基因模型小鼠具有更高表达水平的GRK5。 相似文献
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近年来发现一些G蛋白偶联受体(GPCR)能在细胞膜上形成同源或异源双聚体,并证实受体的双聚化为一些有重要生理功能的GPCR在细胞膜上的表达和信号转导的启动所必需,进一步研究表明,一些GPCR的双聚化不仅可以改变受体与配体结合的特异性和亲和力,而且影响GPCR介导的信号转导的调控,这些结果提示,GPCR之间以及GPCR与其它蛋白在细胞膜上的相互作用是调控GPCR转导信号的一个新途径。 相似文献
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2012年度诺贝尔化学奖授予了美国科学家罗伯特.莱夫科维茨(Robert J.Lefkowitz)和布莱恩.克比尔卡(Brian K.Kobilka),以表彰他们在G蛋白偶联受体研究中的贡献。从Robert J.Lefkowitz最初研究β-肾上腺素受体(β-adrenergic receptor,β-AR)减敏机制时发现β-arrestin1至今已有20多年,随着对β-arrestin在细胞信号转导中作用研究的逐渐深入,发现β-arrestin参与β-AR的减敏、内化和降解;近年来又发现,依赖β-arrestin的β-AR信号转导通路具有"偏向激活"现象,并提示这种依赖β-arrestin的"偏向激活"信号转导通路具有心脏保护作用。β-肾上腺素受体阻滞剂的发现和临床应用被视为20世纪药物治疗学上里程碑式的进展,是药物防治心脏疾病的最伟大突破,很多心血管药物都以β-AR为靶点。但是,由于目前受体药物均是针对受体本身的调控,这样在阻断了受体介导的病理性信号通路和功能的同时,也阻断了受体介导的正常生理性信号通路和功能,造成了严重的毒副作用。所以,研发能选择性阻滞β-AR过度激活介导的病理性信号通路和功能的同时,保留受体介导的正常生理性信号通路和功能(如β-arrestin信号通路)的药物,对治疗心血管疾病有重要意义,受体功能选择性的配体药物将成为未来药物的研究方向。该文将回顾β-arrestin的发现过程,综述其与β-AR的相互作用,期望能为心脏疾病的药物治疗提供参考。 相似文献
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Pascal Maurice Avais M Daulat Rostislav Turecek Klara Ivankova-Susankova Francesco Zamponi Maud Kamal Nathalie Clement Jean-Luc Guillaume Bernhard Bettler C��line Gal��s Philippe Delagrange Ralf Jockers 《The EMBO journal》2010,29(21):3646-3659
Functional asymmetry of G‐protein‐coupled receptor (GPCR) dimers has been reported for an increasing number of cases, but the molecular architecture of signalling units associated to these dimers remains unclear. Here, we characterized the molecular complex of the melatonin MT1 receptor, which directly and constitutively couples to Gi proteins and the regulator of G‐protein signalling (RGS) 20. The molecular organization of the ternary MT1/Gi/RGS20 complex was monitored in its basal and activated state by bioluminescence resonance energy transfer between probes inserted at multiple sites of the complex. On the basis of the reported crystal structures of Gi and the RGS domain, we propose a model wherein one Gi and one RGS20 protein bind to separate protomers of MT1 dimers in a pre‐associated complex that rearranges upon agonist activation. This model was further validated with MT1/MT2 heterodimers. Collectively, our data extend the concept of asymmetry within GPCR dimers, reinforce the notion of receptor specificity for RGS proteins and highlight the advantage of GPCRs organized as dimers in which each protomer fulfils its specific task by binding to different GPCR‐interacting proteins. 相似文献
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Kantamneni S Holman D Wilkinson KA Corrêa SA Feligioni M Ogden S Fraser W Nishimune A Henley JM 《Journal of neurochemistry》2008,107(1):86-95
The neuron-specific G protein-coupled receptor interacting scaffold protein (GISP) is a multidomain, brain-specific protein derived from the A-kinase anchoring protein-9 gene. We originally isolated GISP as an interacting partner for the GABA(B) receptor subunit GABA(B1). Here, we show that the protein tumour susceptibility gene 101 (TSG101), an integral component of the endosomal sorting machinery that targets membrane proteins for lysosomal degradation, also interacts with GISP. TSG101 co-immunoprecipitates with GISP from adult rat brain, and using GST pull-downs, we identified that the eighth coiled-coiled region of GISP is critical for TSG101 association. Intriguingly, although there is no direct interaction between GISP and the GABA(B2) subunit, their co-expression in HEK293 cells increases levels of GABA(B2). GISP also inhibits TSG101-dependent GABA(B2) down-regulation in human embryonic kidney 293 cells whereas over-expression of a mutant GISP lacking the TSG101 binding domain has no effect on GABA(B2) degradation. These data suggest that GISP can function as a negative regulator of TSG101-dependent lysosomal degradation of transmembrane proteins in neurons to promote receptor stability. 相似文献
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Previous studies in our laboratory have shown that in NIH3T3-5HT2A cells, 5-HT-induced AA release is PLA2-coupled and independent of 5-HT2A receptor-mediated PLC activation. Although 5-HT2A receptor-mediated PLC activation is known to be Galphaq-coupled, much less is understood about 5-HT2A receptor-mediated PLA2 activation. Therefore, the studies presented here were aimed at elucidating the signal transduction pathway linking stimulation of the 5-HT2A receptor to PLA2 activation. By employing various selective inhibitors, toxins, and antagonistic peptide constructs, we propose that the 5-HT2A receptor can couple to PLA2 activation through two parallel signaling cascades. Initial experiments were designed to examine the role of pertussis toxin-sensitive G proteins, namely Galphai/o, as well as pertussis toxin-insensitive G proteins, namely Galpha12/13, in 5-HT-induced AA release. Furthermore, inactivation of both Gbetagamma heterodimers and Rho proteins resulted in decreased agonist-induced AA release, without having any effect on PLC-IP accumulation. We also demonstrated 5-HT2A receptor-mediated phosphorylation of ERK1,2 and p38. Moreover, pretreatment with selective ERK1,2 and p38 inhibitors resulted in decreased 5-HT-induced AA release. Taken together, these results suggest that the 5-HT2A receptor expressed in NIH3T3 cells can couple to PLA2 activation though a complex signaling mechanism involving both Galphai/o-associated Gbetagamma-mediated ERK1,2 activation and Galpha12/13-coupled, Rho-mediated p38 activation. 相似文献
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El Messari S Iturrioz X Fassot C De Mota N Roesch D Llorens-Cortes C 《Journal of neurochemistry》2004,90(6):1290-1301
Apelin is a novel neuropeptide involved in the regulation of body fluid homeostasis and cardiovascular functions. It acts through a G protein-coupled receptor, the APJ receptor. We studied the structure-activity relationships of apelin at the rat apelin receptor, tagged at its C-terminal end with enhanced green fluorescent protein and stably expressed in CHO cells. We evaluated the potency of N- and C-terminal deleted fragments of K17F to bind with high affinity to the apelin receptor, and to inhibit cAMP production and to induce apelin receptor internalization. We first characterized the internalization and trafficking of the rat apelin receptor. This receptor was internalized via a clathrin-dependent mechanism and our results suggest that receptor trafficking may follow a recycling pathway. We then tried to identify the amino acids of K17F required for apelin activity. The first five N-terminal and the last two C-terminal amino acids of K17F were not essential for apelin binding or the inhibition of cAMP production. However, the full-length sequence of K17F was the most potent inducer of apelin receptor internalization because successive N-terminal amino-acid deletions progressively reduced internalization and the removal of a single amino acid at the C-terminus abolished this process. Finally, the most novel observation of this work is that hypotensive actions of apelin peptides correlate best with the ability of those ligands to internalize. Thus, apelin receptor signaling and endocytosis are functionally dissociated, possibly reflecting the existence of several conformational states of this receptor, stabilized by the binding of different apelin fragments to the apelin receptor. 相似文献
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Heng T. Duong Zhan-Guo Gao Kenneth A. Jacobson 《Nucleosides, nucleotides & nucleic acids》2013,32(10-12):1507-1517
Residues of the second extracellular loop are believed to be important for ligand recognition in adenosine receptors. Molecular modeling studies have suggested that one such residue, Gln 167 of the human A 3 receptor, is in proximity to the C2 moiety of some adenosine analogs when bound. Here this putative interaction was systematically explored using a neoceptor strategy, i.e., by site-directed mutagenesis and examination of the affinities of nucleosides modified to have complementary functionality. Gln 167 was mutated to Ala, Glu, and Arg, while the 2-position of several adenosine analogs was substituted with amine or carboxylic acid groups. All compounds tested lost affinity to the mutant receptors in comparison to the wild type. However, comparing affinities among the mutant receptors, several compounds bearing charge at the 2-position demonstrated preferential affinity for the mutant receptor bearing a residue of complementary charge. 13, with a positively-charged C2 moiety, displayed an 8.5-fold increase in affinity at the Q167E mutant receptor versus the Q167R mutant receptor. Preferential affinity for specific mutant receptors was also observed for 8 and 12. The data suggests that a direct contact is made between the C2 substituent of some charged ligands and the mutant receptor bearing the opposite charge at position 167. 相似文献
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Dasiel O. Borroto-Escuela Daniel Marcellino Francisco Ciruela 《Biochemical and biophysical research communications》2010,394(1):222-227
Evidence exists that the adenosine receptor A2AR and the dopamine receptor D2R form constitutive heteromers in living cells. Mass spectrometry and pull-down data showed that an arginine-rich domain of the D2R third intracellular loop binds via electrostatic interactions to a specific motif of the A2AR C-terminal tail. It has been indicated that the phosphorylated serine 374 might represent an important residue in this motif. In the present study, it was found that a point mutation of serine 374 to alanine reduced the A2AR ability to interact with D2R. Also, this point mutation abolished the A2AR-mediated inhibition of both the D2R high affinity agonist binding and signaling. These results point to a key role of serine 374 in the A2AR-D2R interface. All together these results indicate that by targeting A2AR serine 374 it will be possible to allosterically modulate A2AR-D2R function, thus representing a new approach for therapeutically modulate D2R function. 相似文献
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Francisco Ciruela 《生物化学与生物物理学报:生物膜》2010,1798(1):9-371
Adenosine is a well known neuromodulator in the central nervous system. As a consequence, adenosine can be beneficial in certain disorders and adenosine receptors will be potential targets for therapy in a variety of diseases. Adenosine receptors are G protein-coupled receptors, and are also expressed in a large variety of cells and tissues. Using these receptors as a paradigm of G protein-coupled receptors, the present review focus on how protein-protein interactions might contribute to neurotransmitter/neuromodulator regulation, based on the fact that accessory proteins impinge on the receptor/G protein interaction and therefore modulate receptor functioning. Besides affecting receptor signaling, these accessory components also play a key role in receptor trafficking, internalization and desensitization, as it will be reviewed here. In conclusion, the finding of an increasing number of adenosine receptors interacting proteins, and specially the molecular and functional integration of these accessory proteins into receptorsomes, will open new perspectives in the understanding of particular disorders where these receptors have been proved to be involved. 相似文献
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Nigrostriatal dopaminergic denervation is associated with complex changes in the functional and neurochemical anatomy of the basal ganglia. The excitatory neurotransmitter glutamate mediates neural signaling at crucial points of this circuitry, and glutamate receptors are differentially distributed in the basal ganglia. Available evidence suggests that the glutamatergic corticostriatal and subthalamofugal pathways become overactive after nigrostriatal dopamine depletion. In this study, we have analyzed the regulation of the GluR1 subunit of the a-amino-3-hydroxy-5-methyl-4-isoxazole propionate glutamate receptor in the basal ganglia of primates following 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced dopamine denervation. The dopamine denervation resulted in distinct alterations in GluR1 distribution: (1) GluR1 protein expression was markedly increased in caudate and putamen, and this was most pronounced in the striosomes; (2) GluR1 protein was altered minimally in subthalamic nucleus; (3) expression of GluR1 was down-regulated in the globus pallidus by 63% and in the substantia nigra by 57%. The down-regulation of GluR1 expression in the output nuclei of the basal ganglia, the internal segment of the globus pallidus and the substantia nigra pars reticulata, may be a compensation for the overactive glutamatergic input from subthalamic nucleus, which arises after striatal dopamine denervation. Our results indicate that the glutamatergic system undergoes regulatory changes in response to altered basal ganglia activity in a primate model of Parkinson's disease. Targeted manipulation of the glutamatergic system may be a viable approach to the symptomatic treatment of Parkinson's disease. 相似文献
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Beilei Lei Daniel P. Morris Michael P. Smith Debra A. Schwinn 《Cellular signalling》2009,21(10):1532-1539
We have reported that the α1A-adrenergic receptor (α1AAR) in rat-1 fibroblasts is a lipid raft protein. Here we examined whether disrupting lipid rafts by methyl-β-cyclodextrin (MCD) sequestration of cholesterol affects α1AAR signaling. Unexpectedly, MCD increased α1AAR-dependent basal inositol phosphate formation and p38 mitogen-activated protein kinase activation in a cholesterol-dependent manner. It also initiated internalization of surface α1AAR, which was partially blocked by receptor inhibition. Binding assays revealed MCD-mediated increases in receptor agonist affinity as well as reciprocal decreases in inverse agonist affinity, a behavior that is usually interpreted as a shift toward the active receptor conformation. In untreated cells a fraction of the receptor was found to be present in preassociated receptor/G protein complexes, which rapidly dissociate upon receptor stimulation. Consistent with MCD-induced signaling, raft disruption resulted in an increase in receptor/G protein complexes. These results strongly suggest that lipid rafts constrain basal α1AAR activity; however, preassembled receptor/G protein complexes could still provide a mechanism for accelerating α1AAR signaling following stimulation. 相似文献
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The Group C G protein-coupled receptors include the metabotropic glutamate receptors (mGluRs), the GABAB receptor, the calcium sensor and several taste receptors, most of which are obligate dimers, indeed recent work has shown that dimerization is necessary for the activation of these receptors. Consequently factors that regulate their ability to homo- or heterodimerize are important. The Group 1 mGluRs include mGluR1 and mGluR5 both of which have splice variants with altered C-termini. In this study, we show that mGluR1b is a dimer and that it does not efficiently heterodimerize with mGluR1a, unlike the two splice variants of mGluR5 that can heterodimerize. Mutation of a positively charged motif (RRKK) at the C-terminus of the mGluR1b tail permits mGluR1b to heterodimerize with mGluR1a. Co-expression of mGluR1a and mGluR1b in COS-7 cells results in the accumulation of mGluR1b in intracellular inclusions that do not contain mGluR1a. This behaviour is mimicked by a chimera of the lymphocyte antigen CD2 with the C-terminus of mGluR1b (pCD1b) and depends on the presence of the RRKK motif. These accumulations are immunoreactive for endoplasmic reticulum (ER) markers, but not Golgi and ERGIC markers. This segregation of mGluR1b from other ER proteins may contribute to its failure to dimerize with mGluR1a. 相似文献