Characterization of [3H]-LY354740 binding to rat mGlu2 and mGlu3 receptors expressed in CHO cells using Semliki Forest virus vectors

Schweitzer, Christophe; Kratzeisen, Claudia; Adam, Geo; Lundström, Kenneth; Malherbe, Pari; Ohresser, Serge; Stadler, Heinz; Wichmann, Jürgen; Woltering, Thomas J.; Mutel, Vincent

doi:10.1016/s0028-3908(99)00265-8

Cited by 70 publications

(56 citation statements)

References 27 publications

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“…Consistent with this model, we found that overexpressing the Gαo dominant negative mutant that displays a low affinity for both GDP and GTP has a direct effect on the ECD dimer dynamics and, indeed, increases agonist potency. The effect observed is consistent with the small decrease in agonist-binding affinity upon GTPγS treatment reported for many mGlu receptors (45).…”

Section: Discussionsupporting

confidence: 88%

Illuminating the activation mechanisms and allosteric properties of metabotropic glutamate receptors

Doumazane

Scholler

Fabre

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

108

147

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In multimeric cell-surface receptors, the conformational changes of the extracellular ligand-binding domains (ECDs) associated with receptor activation remain largely unknown. This is the case for the dimeric metabotropic glutamate receptors even though a number of ECD structures have been solved. Here, using an innovative approach based on cell-surface labeling and FRET, we demonstrate that a reorientation of the ECDs is associated with receptor and G-protein activation. Our approach helps identify partial agonists and highlights allosteric interactions between the effector and binding domains. Any approach expected to stabilize the active conformation of the effector domain increased the agonist potency in stabilizing the active ECDs conformation. These data provide key information on the structural dynamics and drug action at metabotropic glutamate receptors and validate an approach for tackling such analysis on other receptors.M any cell-surface receptors are multimers of proteins composed of several domains (1-3), including extracellular domains (ECDs) involved in endogenous ligand recognition and transmembrane domains (TMDs) responsible for intracellular signal transduction. Analysis of the conformational changes of the ECDs associated with receptor activation is crucial to understand the detailed mechanism involved in receptor activation and for the development of new innovative drugs. However, limited information is available on how the conformational changes in these proteins lead to receptor activation, especially in living cells.The eight glutamate-activated G-protein-coupled receptors (GPCRs), called "metabotropic glutamate receptors" (mGluRs), are key examples of multidomain and multimeric receptors (Fig. 1A). These receptors are strict dimers (4-6), and each subunit is made of a large ECD associated with a seven-helix TMD responsible for G-protein activation and downstream signaling (7). The mGluRs are key elements involved in the regulation of synaptic activity (8), and therefore they represent promising targets in drug development for the treatment of multiple neurologic and psychiatric diseases (9). More generally, the mGluRs are part of the class C GPCR family that contains structurally related receptors such as the receptors for sweet and umami taste, calcium, basic amino acids, and the inhibitory neurotransmitter GABA (10, 11).Crystallographic studies of the isolated dimeric ECDs and mutagenesis analyses have provided a clear view of the structure of the dimeric ECD and of the initial steps of mGluR activation. The ECD is composed of a Venus flytrap (VFT) bilobate domain containing the agonist binding site (12-15) and a cysteine-rich domain (CRD) that connects the VFT to the TMD (16). The VFTs exist in two major states: an open state (o) in absence of ligand and stabilized by antagonists, and a closed state (c) stabilized by agonists and required for receptor activation (12-15). The VFT dimer is in equilibrium between various conformations, depending on whether one or two VFTs are open or cl...

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Section: Discussionsupporting

confidence: 88%

Illuminating the activation mechanisms and allosteric properties of metabotropic glutamate receptors

Doumazane

Scholler

Fabre

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

108

147

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“…The threshold dose for producing a significant reduction was 5 M APDC, and the reduction in extracellular glutamate was reversed by washing out the drug with dialysis buffer. Furthermore, NAAG, a mGluR3 agonist (Wroblewska et al, 1997;Schweitzer et al, 2000) elicited a dose-dependent decrease in extracellular glutamate levels in the nucleus accumbens (Fig. 2, C and D).…”

Section: Mglur2/3 Immunoproteins Are Highly Expressed In the Nucleus mentioning

confidence: 82%

“…To further determine the involvement of the subtypes of group II mGluRs, the effect of the mGluR3 agonist NAAG (Wroblewska et al, 1997;Schweitzer et al, 2000) was examined. NAAG decreased extracellular glutamate levels in the presence of 2-PMPA, an enzyme (NAALADase) inhibitor that prevented NAAG metabolism to glutamate (Slusher et al, 1999).…”

Section: Discussionmentioning

confidence: 99%

“…However, no selective mGluR3 antagonist was available to further verify the role of mGluR3 in modulating endogenous glutamate release. Also, it was reported that NAAG is only 10-fold more selective for mGluR3 than mGluR2 (Cartmell et al, 1998;Schweitzer et al, 2000). Although NAAG may also acts as a weak NMDA agonist, the inhibitory effect of NAAG on glutamate release is unlikely mediated by activating NMDA receptors because previous studies have shown that NMDA receptor activation increases glutamate release in the striatum (Hashimoto et al, 2000).…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Group II Metabotropic Glutamate Receptors Modulate Extracellular Glutamate in the Nucleus Accumbens

Xi¹,

Baker²,

Shen³

et al. 2002

J Pharmacol Exp Ther

196

157

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The regulation of extracellular glutamate in the nucleus accumbens by group II metabotropic glutamate receptors (mGluR2/3) was examined in vivo. Stimulation of mGluR2/3 with 2R,4R-4-aminopyrrolidine-2,4-dicarboxylate (APDC) or N-acetylaspartylglutamate reduced extracellular glutamate levels. Conversely, blockade of mGluR2/3 by LY143495 or (RS)-1-amino-5-phosphonoindan-1-carboxylic acid (APICA) increased extracellular glutamate, an effect antagonized by the coadministration of APDC. These effects likely involve both vesicular and nonvesicular glutamate, because the increase in glutamate by APICA or the decrease by APDC was prevented by blocking N-type calcium channels and the release of glutamate after potassium-induced membrane depolarization was antagonized by APDC. In addition, blockade of the cystine-glutamate exchange, a major nonvesicular source of extracellular glutamate, by (S)-4-carboxyphenylglycine blocked the effects induced by either APDC or APICA. However, blockade of Na ϩ channels by tetrodotoxin or Na ϩ -dependent glutamate transporters by DL-threo-␤-benzyloxyaspartate failed to affect the alterations in extracellular glutamate by APICA or APDC, respectively. Group II mGluRs are G i -coupled and coperfusion with the cAMP-dependent protein kinase (PKA) activator Sp-cAMPS blocked the reduction in glutamate by APDC and the PKA inhibitor Rp-cAMPS prevented the elevation in glutamate by APICA. Taken together, these data support three conclusions: 1) group II mGluRs regulate both vesicular and nonvesicular release of glutamate in the nucleus accumbens, 2) there is tonic in vivo stimulation of mGluR2/3 by endogenous glutamate, and 3) modulation of group II mGluRs of extracellular glutamate is Ca 2ϩ -and PKAdependent.

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“…As with nearly all orthosteric mGlu pharmacological agents there is the underlying issue of selectivity. DCG-IV and LY379268 are reference Group II mGlu agonists, BINA and LY487379 are highly potent PAMs and the recently discovered MNI series of compounds (MNI-135, MNI-136 and MNI-137) are potent negative allosteric modulators (Galici et al, 2006;Hemstapat et al, 2006;Johnson et al, 2003;Linden et al, 2005;Schweitzer et al, 2000). Despite the large array of pharmacological tools available for Group II mGlu receptors, there remains a paucity of ligands that selectively differentiate between mGlu 2 and mGlu 3 , which is due to the high degree of sequence homology between the two.…”

Section: Group II Mglu Receptor Pharmacologymentioning

confidence: 99%

Metabotropic Receptors for Glutamate and GABA

Stewart¹,

Kniazeff²,

Prézeau³

et al. 2012

Pharmacology

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Characterization of [3H]-LY354740 binding to rat mGlu2 and mGlu3 receptors expressed in CHO cells using Semliki Forest virus vectors

Cited by 70 publications

References 27 publications

Illuminating the activation mechanisms and allosteric properties of metabotropic glutamate receptors

Illuminating the activation mechanisms and allosteric properties of metabotropic glutamate receptors

Group II Metabotropic Glutamate Receptors Modulate Extracellular Glutamate in the Nucleus Accumbens

Metabotropic Receptors for Glutamate and GABA

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