Mutational Analysis and Molecular Modeling of the Binding Pocket of the Metabotropic Glutamate 5 Receptor Negative Modulator 2-Methyl-6-(phenylethynyl)-pyridine

Malherbe, Pari; Kratochwil, Nicole A.; Zenner, Marie-Théeése; Piussi, Jenny; Diener, Catherine; Kratzeisen, Claudia; Fischer, Christophe; Porter, Richard H.

doi:10.1124/mol.64.4.823

Cited by 137 publications

(170 citation statements)

References 38 publications

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“…S1). mGlu Δ5Δ retains its ability to bind the NAM [ 3 H]-MPEP with a K d of 8.8 ± 0.7 nM, similar to that reported for the full-length receptor (32) (Fig. S2A).…”

Section: Resultssupporting

confidence: 57%

Distinct roles of metabotropic glutamate receptor dimerization in agonist activation and G-protein coupling

Moustaine

Granier

Doumazane

et al. 2012

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

151

130

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The eight metabotropic glutamate receptors (mGluRs) are key modulators of synaptic transmission and are considered promising targets for the treatment of various brain disorders. Whereas glutamate acts at a large extracellular domain, allosteric modulators have been identified that bind to the seven transmembrane domain (7TM) of these dimeric G-protein-coupled receptors (GPCRs). We show here that the dimeric organization of mGluRs is required for the modulation of active and inactive states of the 7TM by agonists, but is not necessary for G-protein activation. Monomeric mGlu2, either as an isolated 7TM or in full-length, purified and reconstituted into nanodiscs, couples to G proteins upon direct activation by a positive allosteric modulator. However, only a reconstituted full-length dimeric mGlu2 activates G protein upon glutamate binding, suggesting that dimerization is required for glutamate induced activation. These data show that, even for such well characterized GPCR dimers like mGluR2, a single 7TM is sufficient for G-protein coupling. Despite this observation, the necessity of dimeric architecture for signaling induced by the endogenous ligand glutamate confirms that the central core of signaling complex is dimeric.M etabotropic glutamate receptors (mGluRs) play key roles in the modulation of both excitatory and inhibitory synapses in the brain. These eight G-protein-coupled receptors (GPCRs) represent major targets for pharmaceutical companies in search of new treatments for a variety of neurological and psychiatric disorders (1-3). These receptors are part of the class C GPCR family that also includes the GABA B , calcium sensing, and sweet and umami taste receptors, which are all major targets for drug development (4).The structural complexity of class C GPCRs, compared with rhodopsin-like class A GPCRs, offers multiple possibilities in designing molecules that modulate their activity. Not only are mGluRs strict constitutive dimers (5, 6), but each protomer is composed of several domains (7,8). Agonists bind in a bilobate venus fly-trap domain (VFT) (9), which is linked through a cysteine-rich domain (CRD) to the heptahelical transmembrane domain (7TM) that is responsible for G-protein activation (7). The 7TM is the target of a number of synthetic compounds acting either as negative or positive allosteric modulators (NAMs and PAMs, respectively). Given their ability to finely tune endogenous signaling, such compounds present exciting opportunities for drug development (10).The functional mechanism of such a complex machine remains to be characterized, although some critical steps have been well documented. Previous studies have shown that receptor activation results from the closure of the VFT upon agonist binding (9,(11)(12)(13)(14)(15). This conformational change in the extracellular domain is coupled to a conformational change in the intracellular side of at least one 7TM that is responsible for G-protein coupling (16)(17)(18)(19). The mechanism for allosteric communication between the VFT and 7TM ...

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“…S1). mGlu Δ5Δ retains its ability to bind the NAM [ 3 H]-MPEP with a K d of 8.8 ± 0.7 nM, similar to that reported for the full-length receptor (32) (Fig. S2A).…”

Section: Resultssupporting

confidence: 57%

Distinct roles of metabotropic glutamate receptor dimerization in agonist activation and G-protein coupling

Moustaine

Granier

Doumazane

et al. 2012

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

151

130

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“…Slices were perfused with MPEP (5 μM) a selective mGluR5 antagonist (Malherbe et al, 2003) for 40 min, prior to the addition of TNF-α (5 ng/ml). HFS was then applied to the slice 20 min later and the electrophysiological response monitored for 1 h post-tetanus.…”

Section: 3mentioning

confidence: 99%

Evidence for a role for the group I metabotropic glutamate receptor in the inhibitory effect of tumor necrosis factor-α on long-term potentiation

Cumiskey¹,

Butler²,

Moynagh³

et al. 2007

Brain Research

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Pro-inflammatory cytokines are known to be elevated in several neuropathological states that are associated with learning and memory. We have previously demonstrated in our laboratory that the inhibition of long-term potentiation (LTP) in the dentate gyrus region of the rat hippocampus, by tumor necrosis factor (TNF)-α, represents a biphasic response, an early phase dependent on p38 mitogen activated protein kinase (MAPK) activation and a later phase, possible dependent on protein synthesis. Many of the factors involved in the early modulation of LTP by TNF-α have yet to be elucidated. This study investigated if metabotropic glutamate receptors (mGluRs) are functionally linked to the inhibitory effect of TNF-α on LTP in the rat dentate gyrus in vitro. We report that the impairment of early-LTP by TNF-α is significantly attenuated by prior application of the group I/II mGluR antagonist MCPG and more specifically the mGluR5 antagonist MPEP. Since TNF-α is now known to cause transient increases in intracellular Ca 2+ levels from ryanodine-sensitive stores, we explored the possibility that disruption of intracellular Ca 2+ homeostasis could be involved.Ryanodine was found to significantly reverse the inhibition of LTP by TNF-α. From these studies we propose that the TNF-α inhibition of LTP is dependent upon the activation of TNFR1 and mGlu5-receptors. Importantly this study provides the first proof of the involvement of ryanodine-sensitive intracellular Ca 2+ stores in TNF-α mediated inhibition of LTP. IntroductionThe pro-inflammatory cytokine tumor-necrosis factor (TNF)-α is elevated in the brain in a number of neuropathological states including trauma, ischemia, Parkinson's disease, multiple sclerosis and HIV-associated dementia (Iida et al., 2000;Kassiotis and Kollias, 2001;Sriram et al., 2002). The signaling mechanism underlying the ability of TNF-α to cause the cognitive dysfunction associated with many of these conditions has been probed, but to date no clear mechanistic understanding has been reached. TNF-α and IL-1β at pathophysiological levels have been shown by many authors to inhibit long-term potentiation (LTP) in the CA1 and the dentate gyrus regions of the rat hippocampus (Cunningham et al., 1996;Murray and Lynch, 1998;Tancredi et al., 1992) but not by others (Stellwagen and Malenka, 2006). IL-1β has been shown to depress NMDAreceptor mediated field potentials in the dentate gyrus (Coogan B R A I N R E S E A R C H 1 1 3 6 ( 2 0 0 7 ) 1 3 -1 9 ⁎ Corresponding author.

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“…Homology modeling, docking analysis and mutagenesis studies have shown that nine conserved amino acid residues in the 7TM of T1R3 are involved in allosteric modulator binding. The corresponding residues have also been found in the 7TM of CaS [60][61][62][63] and mGlu receptors [64][65][66] . This implies that class C GPCRs share a common binding site for allosteric modulators.…”

Section: Tm Allosteric Sitesmentioning

confidence: 93%

“…Numerous allosteric modulators of group I mGlu receptors have since been identified. It has been proposed that the movement of Trp798 in TM6 of mGlu1 (Trp784 at the homologous position in mGlu5) is essential for receptor activation [66] . The PAMs stabilize the active conformation of this group by facilitating the movement of a conserved Trp in TM6, whereas the NAMs prevent the relative movement between TM6 and TM3 [66] .…”

Section: Ligand Binding Sites Of Four Typical Class C Gpcr Family Memmentioning

confidence: 99%

“…It has been proposed that the movement of Trp798 in TM6 of mGlu1 (Trp784 at the homologous position in mGlu5) is essential for receptor activation [66] . The PAMs stabilize the active conformation of this group by facilitating the movement of a conserved Trp in TM6, whereas the NAMs prevent the relative movement between TM6 and TM3 [66] . For the mGlu5 receptor, most PAMs and NAMs share an overlapping binding pocket that is composed of TM3, 5, 6, and 7 [73] , except for a small number of distinct sites [74] .…”

Section: Ligand Binding Sites Of Four Typical Class C Gpcr Family Memmentioning

confidence: 99%

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Structure and ligand recognition of class C GPCRs

2012

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The G-protein-coupled receptors (GPCRs) are one of the largest super families of cell-surface receptors and play crucial roles in virtually every organ system. One particular family of GPCRs, the class C GPCRs, is distinguished by a characteristically large extracellular domain and constitutive dimerization. The structure and activation mechanism of this family result in potentially unique ligand recognition sites, thereby offering a variety of possibilities by which receptor activity might be modulated using novel compounds. In the present article, we aim to provide an overview of the exact sites and structural features involved in ligand recognition of the class C GPCRs. Furthermore, we demonstrate the precise steps that occur during the receptor activation process, which underlie the possibilities by which receptor function may be altered by different approaches. Finally, we use four typical family members to illustrate orthosteric and allosteric sites with representative ligands and their corresponding therapeutic potential.

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Mutational Analysis and Molecular Modeling of the Binding Pocket of the Metabotropic Glutamate 5 Receptor Negative Modulator 2-Methyl-6-(phenylethynyl)-pyridine

Cited by 137 publications

References 38 publications

Distinct roles of metabotropic glutamate receptor dimerization in agonist activation and G-protein coupling

Distinct roles of metabotropic glutamate receptor dimerization in agonist activation and G-protein coupling

Evidence for a role for the group I metabotropic glutamate receptor in the inhibitory effect of tumor necrosis factor-α on long-term potentiation

Structure and ligand recognition of class C GPCRs

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