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1.
The serotonin1A receptor is an important member of the G-protein coupled receptor family, and is involved in the generation and modulation of a variety of cognitive, behavioral, and developmental functions. We have monitored the ligand binding of the human serotonin1A receptor stably expressed in CHO cells (termed CHO-5-HT1AR) following treatment with sphingomyelinase (SMase), an enzyme that specifically catalyzes the hydrolysis of sphingomyelin into ceramide and phosphorylcholine. Our results show, for the first time, that the specific ligand binding activity of the serotonin1A receptor in membranes isolated from CHO-5-HT1AR cells is increased upon sphingomyelinase treatment. Saturation binding analysis reveals increase in binding affinity of the receptor under these conditions. This is accompanied by a reduction in membrane order, as monitored by fluorescence anisotropy of the membrane probe 1-[4-(trimethylammonio)phenyl]-6-phenyl-1,3,5-hexatriene (TMA-DPH) in intact cells. These results represent the first report on the effect of sphingomyelinase treatment on the ligand binding activity of this important neurotransmitter receptor. 相似文献
2.
Eszter Hazai Prasad Joshi Edward C. Skoviak Asha Suryanarayanan Marvin K. Schulte Zsolt Bikadi 《Bioorganic & medicinal chemistry》2009,17(16):5796-5805
Serotonin type 3 receptors (5-HT3R) are members of the ligand gated ion channel receptor family. In this study, the interactions of the agonists serotonin (5-HT) and m-chlorophenylbiguanidine (mCPBG) at the binding site of the 5-HT3AR were investigated at an atomic level. Site-directed mutagenesis studies in Loop B and E along with our earlier published results from mutations within Loops A, C, and D provide comprehensive data on the interaction of 5-HT and mCPBG with 5-HT3ARs. Using this data we have constructed a refined homology model of the 5-HT3AR that considers all of the available experimental data. 5-HT and mCPBG were docked into the newly constructed homology model and the amino acid residues critical in binding of these agonists were compared and analyzed. Our docking results reveal many similar binding interactions for 5-HT and mCPBG. Namely, residues THR181, TRP183, PHE226, ILE228, TYR234 and GLU129 were all found to play key roles in binding of both 5-HT and mCPBG. However, the results also revealed two important differences that exist between the interactions of the two agonists. In our model, a hydrogen bond is formed between the indole hydrogen of 5-HT and the residue TYR153. This interaction is not present in the case of mCPBG. Conversely, a hydrogen bond exists between SER182 and a protonated nitrogen of mCPBG, which does not exist in 5-HT. Our modeling results were found to be in accordance with experimental data. 相似文献
3.
Xavier Vi?als Estefanía Moreno Laurence Lanfumey Arnau Cordomí Antoni Pastor Rafael de La Torre Paola Gasperini Gemma Navarro Lesley A. Howell Leonardo Pardo Carmen Lluís Enric I. Canela Peter J. McCormick Rafael Maldonado Patricia Robledo 《PLoS biology》2015,13(7)
Activation of cannabinoid CB1 receptors (CB1R) by delta9-tetrahydrocannabinol (THC) produces a variety of negative effects with major consequences in cannabis users that constitute important drawbacks for the use of cannabinoids as therapeutic agents. For this reason, there is a tremendous medical interest in harnessing the beneficial effects of THC. Behavioral studies carried out in mice lacking 5-HT2A receptors (5-HT2AR) revealed a remarkable 5-HT2AR-dependent dissociation in the beneficial antinociceptive effects of THC and its detrimental amnesic properties. We found that specific effects of THC such as memory deficits, anxiolytic-like effects, and social interaction are under the control of 5-HT2AR, but its acute hypolocomotor, hypothermic, anxiogenic, and antinociceptive effects are not. In biochemical studies, we show that CB1R and 5-HT2AR form heteromers that are expressed and functionally active in specific brain regions involved in memory impairment. Remarkably, our functional data shows that costimulation of both receptors by agonists reduces cell signaling, antagonist binding to one receptor blocks signaling of the interacting receptor, and heteromer formation leads to a switch in G-protein coupling for 5-HT2AR from Gq to Gi proteins. Synthetic peptides with the sequence of transmembrane helices 5 and 6 of CB1R, fused to a cell-penetrating peptide, were able to disrupt receptor heteromerization in vivo, leading to a selective abrogation of memory impairments caused by exposure to THC. These data reveal a novel molecular mechanism for the functional interaction between CB1R and 5-HT2AR mediating cognitive impairment. CB1R-5-HT2AR heteromers are thus good targets to dissociate the cognitive deficits induced by THC from its beneficial antinociceptive properties. 相似文献
4.
José L. Moreno Carolina Muguruza Adrienne Umali Steven Mortillo Terrell Holloway Fuencisla Pilar-Cuéllar Giuseppe Mocci Jeremy Seto Luis F. Callado Rachael L. Neve Graeme Milligan Stuart C. Sealfon Juan F. López-Giménez J. Javier Meana Deanna L. Benson Javier González-Maeso 《The Journal of biological chemistry》2012,287(53):44301-44319
Serotonin and glutamate G protein-coupled receptor (GPCR) neurotransmission affects cognition and perception in humans and rodents. GPCRs are capable of forming heteromeric complexes that differentially alter cell signaling, but the role of this structural arrangement in modulating behavior remains unknown. Here, we identified three residues located at the intracellular end of transmembrane domain four that are necessary for the metabotropic glutamate 2 (mGlu2) receptor to be assembled as a GPCR heteromer with the serotonin 5-hydroxytryptamine 2A (5-HT2A) receptor in the mouse frontal cortex. Substitution of these residues (Ala-6774.40, Ala-6814.44, and Ala-6854.48) leads to absence of 5-HT2A·mGlu2 receptor complex formation, an effect that is associated with a decrease in their heteromeric ligand binding interaction. Disruption of heteromeric expression with mGlu2 attenuates the psychosis-like effects induced in mice by hallucinogenic 5-HT2A agonists. Furthermore, the ligand binding interaction between the components of the 5-HT2A·mGlu2 receptor heterocomplex is up-regulated in the frontal cortex of schizophrenic subjects as compared with controls. Together, these findings provide structural evidence for the unique behavioral function of a GPCR heteromer. 相似文献
5.
1. The serotonin1A (5-HT1A) receptor is an important representative of G-protein coupled family of receptors. It is the most extensively studied among the serotonin receptors, and appears to be involved in various behavioral and cognitive functions.2. We report here the pharmacological and functional characterization of the human serotonin1A receptor stably expressed in HN2 cell line, which is a hybrid cell line between hippocampal cells and mouse neuroblastoma.3. Our results show that serotonin1A receptors in HN2-5-HT1AR cells display ligand-binding properties that closely mimic binding properties observed with native receptors. We further demonstrate that the differential discrimination of G-protein coupling by the specific agonist and antagonist, a hallmark of the native receptor, is maintained for the receptor in HN2-5-HT1AR cells. Importantly, the serotonin1A receptor in HN2-5-HT1AR cells shows efficient downstream signalling by reducing cellular cyclic AMP levels.4. We conclude that serotonin1A receptors expressed in HN2-5-HT1AR cells represent a useful model system to study serotonin1A receptor biology, and is a potential system for solubilization and purification of the receptor in native-like membrane environment. 相似文献
6.
Stevan Pecic Pooja Makkar Sandeep Chaudhary Boojala V. Reddy Hernan A. Navarro Wayne W. Harding 《Bioorganic & medicinal chemistry》2010,18(15):5562-5575
Analogs of nantenine were docked into a modeled structure of the human 5-HT2A receptor using ICM Pro, GLIDE, and GOLD docking methods. The resultant docking scores were used to correlate with observed in vitro apparent affinity (Ke) data. The GOLD docking algorithm when used with a homology model of 5-HT2A, based on a bovine rhodopsin template and built by the program MODELLER, gives results which are most in agreement with the in vitro results. Further analysis of the docking poses among members of a C1 alkyl series of nantenine analogs, indicate that they bind to the receptor in a similar orientation, but differently than nantenine. Besides an important interaction between the protonated nitrogen of the C1 alkyl analogs and residue Asp155, we identified Ser242, Phe234, and Gly238 as key residues responsible for the affinity of these compounds for the 5-HT2A receptor. Specifically, the ability of some of these analogs to establish a H-bond with Ser242 and hydrophobic interactions with Phe234 and Gly238 appears to explain their enhanced affinity as compared to nantenine. 相似文献
7.
MAGI proteins are Membrane-Associated Guanylate Kinase Inverted proteins that belong to the MAGUK family. They are scaffolding proteins that were shown to mediate the trafficking and signaling of various G protein-coupled receptors (GPCRs). They contain PDZ domains in their structure and many GPCRs interact with these proteins via the PDZ motifs on the carboxyl terminal end of a receptor. In a PDZ overlay assay performed with the carboxyl terminal tail of 5-HT2AR, we were able to detect all three members of the MAGI subfamily, MAGI-1, MAGI-2 and MAGI-3 as interacting PDZ proteins. The PDZ motif of 5-HT2AR consists of three amino acids; serine (S), cysteine (C) and valine (V). In this study, we characterize these 5-HT2AR interactions with MAGI proteins. We first confirm the interaction using co-immunopricipitation and illustrate that the interaction is PDZ motif-dependent in human embryonic kidney (HEK 293) cells. We then assess the effects of overexpression and knockdown of the MAGI proteins on the internalization, trafficking and signaling of 5-HT2AR. We find that knockdown of either MAGI-1 or MAGI-3 using siRNA results in a significant reduction in the internalization of 5-HT2AR. As for signaling, we report here that MAGI proteins can modulate the signaling via the two transduction pathways that 5-HT2AR can activate. We illustrate a significant effect of modulating MAGI proteins expression on 5-HT-stimulated IP formation. We demonstrate an enhancement in 5-HT2AR-stimulated IP formation upon MAGI proteins overexpression. In addition, we show that knockdown of MAGI proteins with siRNA leads to a significant reduction in 5-HT2AR-stimulated IP formation. Furthermore, we illustrate a significant increase in 5-HT-stimulated ERK1/2 phosphorylation upon MAGI proteins knockdown. Interestingly, this effect on ERK1/2 activation is PDZ motif-independent. We also suggest two possible mechanisms of regulation for the effect of MAGI proteins on 5-HT2AR function. One mechanism involves the regulation of cell surface expression since we show that both MAGI-2 and MAGI-3 can enhance receptor trafficking to the plasma membrane when overexpressed in HEK 293 cells. The other mechanism points to regulation of second messengers in the signaling pathways. Specifically, we show that overexpression of any of the three MAGI proteins can enhance the recruitment of PLCβ3 to 5-HT2AR. In addition, we report a negative effect for knocking down MAGI-3 on β-arrestin recruitment to the receptor and this effect is PDZ motif-independent. Taken together, our findings document distinct roles for the three MAGI proteins in regulating 5-HT2AR trafficking and signaling and emphasize the importance of studying PDZ proteins and their interactions with GPCRs to regulate their function. 相似文献
8.
Vaishali Javadekar-Subhedar 《Molecular membrane biology》2013,30(2):119-123
The ligand binding and G-protein coupling of the bovine hippocampal 5-HT1A receptor as a function of temperature was monitored. There is an almost complete and irreversible loss in agonist binding at 50°C. However, the antagonist binding is reduced only by 50%, and this could be reversed if the temperature is lowered to 25°C. Interestingly, the agonist binding of the 5-HT1A receptor in membranes exposed to 50°C is inhibited to a much lesser extent by GTP-γ-S, a non-hydrolysable analogue of GTP, indicating uncoupling of the 5-HT1A receptor to G-proteins at 50°C. We propose that high temperature selectively and irreversibly inactivates G-proteins thereby affecting G-protein-receptor interaction and agonist binding of the 5-HT1A receptor. 相似文献
9.
The Serotonin
1A A
Receptor: A Representative Member of the Serotonin Receptor Family 总被引:7,自引:0,他引:7
1. Serotonin is an intrinsically fluorescent biogenic amine that acts as a neurotransmitter and is found in a wide variety of sites in the central and peripheral nervous system. Serotonergic signaling appears to play a key role in the generation and modulation of various cognitive and behavioral functions.2. Serotonin exerts its diverse actions by binding to distinct cell surface receptors which have been classified into many groups. The serotonin1A (5-HT1A) receptor is the most extensively studied of the serotonin receptors and belongs to the large family of seven transmembrane domain G-protein coupled receptors.3. The tissue and sub-cellular distribution, structural characteristics, signaling of the serotonin1A receptor and its interaction with G-proteins are discussed.4. The pharmacology of serotonin1A receptors is reviewed in terms of binding of agonists and antagonists and sensitivity of their binding to guanine nucleotides.5. Membrane biology of 5-HT1A receptors is presented using the bovine hippocampal serotonin1A receptor as a model system. The ligand binding activity and G-protein coupling of the receptor is modulated by membrane cholesterol thereby indicating the requirement of cholesterol in maintaining the receptor organization and function. This, along with the reported detergent resistance characteristics of the receptor, raises important questions on the role of membrane lipids and domains in the function of this receptor. 相似文献
10.
Sébastien Dilly Amaury Graulich Jean-François Liégeois 《Bioorganic & medicinal chemistry letters》2010,20(3):1118-1123
The main feature of many drugs having a 5-HT1A affinity is the presence of an arylpiperazine moiety. Indeed, the protonated nitrogen and the aromatic ring of the arylpiperazine compounds are considered crucial for the interaction with the receptor. However, the replacement of the piperazine moiety by a 1,2,3,6-tetrahydropyridine ring in 4-arylpiperazine-ethyl carboxamide derivatives was recently shown to be highly favourable for 5-HT1A affinity. In order to better understand the favourable effect of this chemical modification, we performed a conformational analysis of these compounds mainly based on the position of the phenyl ring relative to the piperazine and tetrahydropyridine moiety. In the piperazine compounds, the phenyl ring preferentially adopts a perpendicular orientation, whereas an almost planar orientation seems to be the most favourable conformation for the tetrahydropyridine compounds. Therefore, this conformational difference appears as a key for a better interaction with the receptor binding site. This result will serve for the designing high-affinity 5-HT1A ligands. 相似文献
11.
Nora L. Sullivan Nora L. Sullivan Andrew J. Thompson Kerry L. Price 《Molecular membrane biology》2013,30(5):442-451
The ligand binding pocket of Cys-loop receptors consists of a number of binding loops termed A–F. Here we examine the 5-HT3 receptor loop A residues Asn-128, Glu-129 and Phe-130 using modelling, mutagenesis, radioligand binding and functional studies on HEK 293 cells. Replacement of Asn-128 results in receptors that have wild type [3H]granisetron binding characteristics but large changes (ranging from a five-fold decrease to a 1500-fold increase) in the 5-HT EC50 when compared to wild type receptors. Phe-130 mutant receptors show both increases and decreases in Kd and EC50 values, depending on the amino acid substituted. The most critical of these residues appears to be Glu-129; its replacement with a range of other amino acids results in non-binding and non-functional receptors. Lack of binding and function in some, but not all, of these receptors is due to poor membrane expression. These data suggest that Glu-129 is important primarily for receptor expression, although it may also play a role in ligand binding; Phe-130 is important for both ligand binding and receptor function, and Asn-128 plays a larger role in receptor function than ligand binding. In light of these results, we have created two new homology models of the 5-HT3 receptor, with alternative positions of loop A. In our preferred model Glu-129 and Phe-130 contribute to the binding site, while the location of Asn-128 immediately behind the binding pocket could contribute to the conformation changes that result in receptor gating. This study provides a new model of the 5-HT3 receptor binding pocket, and also highlights the importance of experimental data to support modelling studies. 相似文献
12.
A. Gandhimathi 《Journal of biomolecular structure & dynamics》2016,34(5):952-970
The serotonin receptors, also known as 5-hydroxytryptamine (5-HT) receptors, are a group of G protein-coupled receptors (GPCRs) and ligand-gated ion channels found in the central and peripheral nervous systems. GPCRs have a characteristic feature of activating different signalling pathways upon ligand binding and these ligands display several efficacy levels to differentially activate the receptor. GPCRs are primary drug targets due to their central role in several signal transduction pathways. Drug design for GPCRs is also most challenging due to their inherent promiscuity in ligand recognition, which gives rise to several side effects of existing drugs. Here, we have performed the ligand interaction study using the two prominent states of GPCR, namely the active and inactive state of the 5-HT2A receptor. Active state of 5-HT2A receptor model enhances the understanding of conformational difference which influences the ligand-binding site. A 5-HT2A receptor active state model was constructed by homology modelling using active state β2-adrenergic receptor (β2-AR). In addition, virtual screening and docking studies with both active and inactive state models reveal potential small molecule hits which could be considered as agonist-like and antagonist-like molecules. The results from the all-atom molecular dynamics simulations further confirmed that agonists and antagonists interact in different modes with the receptor. 相似文献
13.
Zoe Barclay Louise Dickson Derek Robertson Melanie Johnson Pamela Holland Roberta Rosie Liting Sun Helen Jerina Eve Lutz Sue Fleetwood-Walker Rory Mitchell 《Cellular signalling》2013,25(4):814-821
The 5-HT2A receptor (5-HT2AR) is implicated in psychotropic changes within the central nervous system (CNS). A number of polymorphisms have been reported in the 5-HT2AR gene; one of these results in a non-synonymous change, H452Y, in the carboxy-terminal tail of the receptor protein. The minor allele (9% occurrence) has been statistically associated with CNS dysfunction such as impaired memory processing and resistance to neuroleptic treatment in schizophrenic patients. We investigated the impact of H452Y mutation of the 5-HT2AR expressed in COS7 cells on distinctly coupled intracellular signalling pathways from the receptor, focusing on the heterotrimeric G protein-independent phospholipase D (PLD) pathway, compared to the conventional Gq/11-linked phospholipase C (PLC) pathway. The H452Y mutation selectively attenuated PLD signalling, which as in the wild-type receptor, was mediated by a molecular complex involving PLD1 docked to the receptor's carboxy-terminal tail domain. Co-immunoprecipitation and GST-fusion protein experiments revealed that the H452Y mutation selectively reduced PLD1 binding to the receptor. Experiments with blocking peptides to mimic short sections of the 5-HT2AR tail sequence revealed that the peptide spanning residue 452 strongly reduced PLD but not PLC responses of the receptor. Similar observations were made when assessing both PLD responses and PLD-dependent cellular proliferation elicited by activation of 5-HT2ARs natively expressed in MCF-7 cells. Overall these findings indicate that the H452Y polymorphic variant of the 5-HT2AR displays selective disruption of its PLD signalling pathway. This may potentially play a role in the CNS dysfunction associated with the H452Y allele of the 5-HT2AR. 相似文献
14.
Jin-Jye Feng Fong-Chi Cheng Chun-Hsiung Lin Jiann-Wu Wei Shiaw-Der Yang 《Archives of biochemistry and biophysics》2011,506(1):66
[3H]8-OH-DPAT is a selective ligand for labeling 5-HT1A receptor sites. In competition binding experiments, we found that classic biogenic amine transporter inhibitors displaced [3H]8-OH-DPAT binding at its high-affinity binding sites in HeLaS3 cells. [125I]RTI-55 and [3H]paroxetine are known to specifically label amine transporter sites, and this was observed in our cells. Displacement studies showed that 8-OH-DPAT displayed affinity in a dose-dependent manner for the labeled amine transporter sites. These data suggest that [3H]8-OH-DPAT binds to amine uptake sites in HeLaS3 cells. A variety of drugs targeting different classes of receptors did not significantly affect [3H]8-OH-DPAT binding. Moreover, we determined the specific binding effects of various serotonergic ligands (i.e. [125I]cyanopindolol, [3H]ketanserin/[3H]mesulergine, [3H]GR-65630, [3H]GR-113808 and [3H]LSD) that specifically labeled 5-HT1, 5-HT2, 5-HT3, 5-HT4 and 5-HT5–7 receptors, respectively. It is suggested that HeLaS3 cells contain distinct types of the related to 5-HT receptor recognition binding sites. These observations could help elucidate the relevant characteristics of different types of 5-HT receptors and 5-HT membrane transporters in tumor cells and their role in tumorigenesis. 相似文献
15.
《Bioorganic & medicinal chemistry》2016,24(21):5353-5356
Positron emission tomography (PET) investigations of the 5-HT2A receptor (5-HT2AR) system can be used as a research tool in diseases such as depression, Alzheimer’s disease and schizophrenia. We have previously developed a 11C-labeled agonist PET ligand ([11C]Cimbi-36), and the aim of this study was to identify a 18F-labeled analogue of this PET-ligand. Thus, we developed a convergent radiochemical approach giving easy access to 5 different 18F-labeled ligands structurally related to Cimbi-36 from a common 18F-labeled intermediate. After intravenous injection, all ligands entered the pig brain. However, since within-scan intervention with ketanserin, a known orthosteric 5-HT2A receptor antagonist, did not result in significant blocking, the radioligands seem unsuitable for neuroimaging of the 5-HT2AR in vivo. 相似文献
16.
E. K. Nénonéné F. Radja M. Carli L. Grondin T. A. Reader 《Journal of neurochemistry》1994,62(5):1822-1834
Abstract: The selective serotonin (5-HT) agonist 8-hydroxydipropylaminotetralin (8-OH-DPAT) has been extensively used to characterize the physiological, biochemical, and behavioral features of the 5-HT1A receptor. A further characterization of this receptor subtype was conducted with membrane preparations from rat cerebral cortex and hippocampus. The saturation binding isotherms of [3H]8- OH-DPAT (free ligand from 200 pM to 160 nM) revealed high-affinity 5-HT1A receptors (KH= 0.7–0.8 nM) and lowaffinity (KL= 22–36 nM) binding sites. The kinetics of [3H]8-OH-DPAT binding were examined at two ligand concentrations, i.e., 1 and 10 nM, and in each case revealed two dissociation rate constants supporting the existence of high- and low-affinity binding sites. When the high-affinity sites were labeled with a 1 nM concentration of [3H]8- OH-DPAT, the competition curves of agonist and antagonist drugs were best fit to a two-site model, indicating the presence of two different 5-HT1A binding sites or, alternatively, two affinity states, tentatively designated as 5-HT1AHIGH and 5-HT1ALOW. However, the low correlation between the affinities of various drugs for these sites indicates the existence of different and independent binding sites. To determine whether 5-HT1A sites are modulated by 5′-guanylylimidodiphosphate, inhibition experiments with 5-HT were performed in the presence or in the absence of 100 μM 5′-guanylylimidodiphosphate. The binding of 1 nM [3H]8-OH-DPAT to the 5-HT1AHIGH site was dramatically (80%) reduced by 5′-guanylylimidodiphosphate; in contrast, the low-affinity site, or 5-HT1ALOW, was seemingly insensitive to the guanine nucleotide. The findings suggest that the high-affinity 5-HT1AHIGH site corresponds to the classic 5-HT1A receptor, whereas the novel 5-HT1ALOW binding site, labeled by 1 nM [3H]8-OH-DPAT and having a micromolar affinity for 5-HT, may not belong to the G protein family of receptors. To further investigate the relationship of 5-HT1A sites and the 5-HT innervation, rats were treated with p-chlorophenylalanine or with the neurotoxin p-chloroamphetamine. The inhibition of 5-HT synthesis by p-chlorophenylalanine did not alter either of the two 5-HT1A sites, but deafferentation by p-chloroamphetamine caused a loss of the low-affinity [3H]8-OH- DPAT binding sites, indicating-that these novel binding sites may be located presynaptically on 5-HT fibers and/or nerve terminals. 相似文献
17.
Dow P. Hurst Alan Grossfield Diane L. Lynch Scott Feller Tod D. Romo Klaus Gawrisch Michael C. Pitman Patricia H. Reggio 《The Journal of biological chemistry》2010,285(23):17954-17964
Recent isothiocyanate covalent labeling studies have suggested that a classical cannabinoid, (−)-7′-isothiocyanato-11-hydroxy-1′,1′dimethylheptyl-hexahydrocannabinol (AM841), enters the cannabinoid CB2 receptor via the lipid bilayer (Pei, Y., Mercier, R. W., Anday, J. K., Thakur, G. A., Zvonok, A. M., Hurst, D., Reggio, P. H., Janero, D. R., and Makriyannis, A. (2008) Chem. Biol. 15, 1207–1219). However, the sequence of steps involved in such a lipid pathway entry has not yet been elucidated. Here, we test the hypothesis that the endogenous cannabinoid sn-2-arachidonoylglycerol (2-AG) attains access to the CB2 receptor via the lipid bilayer. To this end, we have employed microsecond time scale all-atom molecular dynamics (MD) simulations of the interaction of 2-AG with CB2 via a palmitoyl-oleoyl-phosphatidylcholine lipid bilayer. Results suggest the following: 1) 2-AG first partitions out of bulk lipid at the transmembrane α-helix (TMH) 6/7 interface; 2) 2-AG then enters the CB2 receptor binding pocket by passing between TMH6 and TMH7; 3) the entrance of the 2-AG headgroup into the CB2 binding pocket is sufficient to trigger breaking of the intracellular TMH3/6 ionic lock and the movement of the TMH6 intracellular end away from TMH3; and 4) subsequent to protonation at D3.49/D6.30, further 2-AG entry into the ligand binding pocket results in both a W6.48 toggle switch change and a large influx of water. To our knowledge, this is the first demonstration via unbiased molecular dynamics that a ligand can access the binding pocket of a class A G protein-coupled receptor via the lipid bilayer and the first demonstration via molecular dynamics of G protein-coupled receptor activation triggered by a ligand binding event. 相似文献
18.
Ádám Andor Kelemen Grzegorz Satała Andrzej J. Bojarski György M. Keserű 《Bioorganic & medicinal chemistry letters》2018,28(14):2418-2421
Here we report the design and synthesis of spiro[pyrrolidine-3,3′-oxindole] derivatives representing a novel scaffold of 5-HT7 receptor ligands. The synthesized analogues were validated as low nanomolar ligands showing selectivity in a panel of related serotonin receptor subtypes including 5-HT1AR, 5-HT2AR and 5-HT6R. 相似文献
19.
Guido M. Gaietta Elizabeth J. Yoder Tom Deerinck Karen Kinder Abraham Hanono Areum Han Chun Wu Mark H. Ellisman 《Brain Cell Biology》2003,32(4):373-380
Pharmacological approaches and optical recordings have shown that Schwann cells of a myelinating phenotype are activated by 5-HT upon its interaction with the 5-HT2A receptor (5-HT2AR). In order to further characterize the expression and distribution of this receptor in Schwann cells, we examined rat sciatic nerve and cultured rat Schwann cells using probes specific to 5-HT2AR protein mRNA. We also examined the endogenous sources of 5-HT in rat sciatic nerve by employing both histochemical stains and an antibody that specifically recognizes 5-HT. Rat Schwann cells of a myelinating phenotype contained both 5-HT2AR protein and mRNA. In the healthy adult rat sciatic nerve, 5-HT2ARs were evenly distributed along the outermost portion of the Schwann cell plasma membrane and within the cytoplasm. The most prominent source of 5-HT was within granules of the endoneurial mast cells, closely juxtaposed to Schwann cells within myelinating sciatic nerves. These results support the hypothesis that the 5-HT receptors expressed by rat Schwann cells in vivo are activated by the release of 5-HT from neighboring mast cells. 相似文献
20.
The 5-hydroxytryptamine 2A receptor (5-HT2AR) undergoes constitutive and agonist-dependent internalization. Despite many advances in our understanding of G protein-coupled receptor trafficking, the exact mechanism of endocytic sorting of G protein-coupled receptors remains obscure. Recently, we have reported a novel finding documenting a global role for the ubiquitin ligase c-Cbl in regulating vesicular sorting of epidermal growth factor receptor (Baldys, A., Göoz, M., Morinelli, T. A., Lee, M. H., Raymond, J. R., Jr., Luttrell, L. M., and Raymond, J. R., Sr. (2009) Biochemistry 48, 1462–1473). Thus, we tested the hypothesis that c-Cbl might play a role in 5-HT2AR recycling. In this study, we demonstrated an association of 5-HT2AR with c-Cbl. Furthermore, down-regulation of c-Cbl by RNA interference blocked efficient recycling of 5-HT2AR to the plasma membrane. Immunofluorescence microscopy revealed that 5-HT2A receptors were trapped in early endosome antigen 1- and Rab11-positive sorting endosomes in cells overexpressing c-Cbl mutants lacking carboxyl termini. This inhibitory effect was associated with a relative decrease in association of c-Cbl truncation proteins with the 5-HT2AR, compared with that observed for the full-length c-Cbl fusion protein. Consistent with the delayed recycling, 5-HT2AR resensitization was greatly attenuated in the presence of c-Cbl mutants lacking carboxyl termini, as detected by changes in the cytosolic calcium. Taken together, these studies have led to the discovery that the C-terminal region of c-Cbl plays a crucial role in the temporal and spatial control of 5-HT2AR recycling. 相似文献