Identification of Critical Residues in the Amino Terminal Domain of the Human NR2B Subunit Involved in the RO 25-6981 Binding Pocket

Malherbe, Pari; Mutel, Vincent; Broger, Clemens; Perin-Dureau, Florent; Kemp, John A.; Neyton, Jacques; Paoletti, Pierre; Kew, James N.C.

doi:10.1124/jpet.103.056291

Cited by 55 publications

(50 citation statements)

References 31 publications

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“…This study and previous work (Perin-Dureau et al, 2002;Malherbe et al, 2003) show that the NR2B NTD is capable of binding two ligands of very distinct chemical nature, the Zn ion and bis-(phenylalkyl)amines such as ifenprodil. Kinetic analysis indicates that Zn and ifenprodil interact in a competitive manner (Fig.…”

Section: Discussionsupporting

confidence: 64%

“…In both NMDA and AMPA/kainate receptors, the NTD is a major, but not the sole, determinant of subtype-specific subunit assembly (Leuschner and Hoch, 1999;Ayalon and Stern-Bach, 2001;Meddows et al, 2001). Recent studies have also shown that, in certain NMDA receptor subunits, the NTD modulates ion channel gating through binding of extracellular allosteric modulators: Zn in the case of the NR2A subunit (Choi and Lipton, 1999;Fayyazuddin et al, 2000;Low et al, 2000;Paoletti et al, 2000) and the noncompetitive synthetic antagonist ifenprodil and its derivatives in the case of NR2B (Perin-Dureau et al, 2002;Malherbe et al, 2003). Because Zn is known to be concentrated and released during activity at many glutamatergic synapses in the CNS (Frederickson et al, 2000), it appears to be a likely candidate as the endogenous ligand of the NTD of NR2A.…”

Section: Introductionmentioning

confidence: 99%

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The Micromolar Zinc-Binding Domain on the NMDA Receptor Subunit NR2B

Rachline¹,

Perin-Dureau²,

Goff³

et al. 2005

J. Neurosci.

213

222

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Eukaryotic ionotropic glutamate receptor subunits possess a large N-terminal domain (NTD) distinct from the neighboring agonistbinding domain. In NMDA receptors, the NTDs of NR2A and NR2B form modulatory domains binding allosteric inhibitors. Despite a high sequence homology, these two domains have been shown to bind two ligands of strikingly different chemical nature. Whereas the NTD of NR2A binds zinc with high (nanomolar) affinity, the NTD of NR2B binds the synthetic neuroprotectant ifenprodil and its derivatives. Using both NTD-mutated/deleted receptors and isolated NTDs, we now show that the NTD of NR2B, in contrast to NR2C and NR2D, also binds zinc, but with a lower affinity. Furthermore, we present evidence that zinc and ifenprodil compete for an overlapping binding site. This modulatory binding site accounts for the submicromolar zinc inhibition of NR1/NR2B receptors. Given that zinc is accumulated and released at many glutamatergic synapses in the CNS, these findings suggest that zinc is the endogenous ligand of the NTD of both NR2A and NR2B, the two major NR2 subunits. Thus, NMDA receptors contain zinc sensors capable of detecting extracellular zinc over a wide concentration range depending on their NR2 subunit composition. The coexistence of subunit-specific zinc-binding sites of high (nanomolar) and low (micromolar) affinity on NMDA receptors raises the possibility that zinc exerts both a tonic and a phasic control of membrane excitability.

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Section: Discussionsupporting

confidence: 64%

Section: Introductionmentioning

confidence: 99%

The Micromolar Zinc-Binding Domain on the NMDA Receptor Subunit NR2B

Rachline¹,

Perin-Dureau²,

Goff³

et al. 2005

J. Neurosci.

213

222

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“…Ifenprodil was identified as a GluN1/GluN2B selective inhibitor (Williams, 1993) and originally was thought to solely bind to the GluN2B ATD (Perin-Dureau et al, 2002;Malherbe et al, 2003;Wong et al, 2005;Ng et al, 2008). Ifenprodil preferentially binds the receptor in open and desensitized conformations (Kew et al, 1996) and reduces the duration of the long openings and open probability of the receptor in cultured hippocampal neurons (Legendre and Westbrook, 1991) and in hippocampal slices from newborn rats (Pina-Crespo and Gibb, 2002).…”

Section: Discussionmentioning

confidence: 99%

Effect of Ifenprodil on GluN1/GluN2B N-Methyl-D-aspartate Receptor Gating

et al. 2012

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Ifenprodil is an allosteric inhibitor of GluN1/GluN2B N-methyl-Daspartate receptors. Despite its widespread use as a prototype for drug development and a subtype-selective tool for physiologic experiments, its precise effect on GluN1/GluN2B gating is yet to be fully understood. Interestingly, recent crystallographic evidence identified that ifenprodil, unlike zinc, binds at the interface of the GluN1/GluN2B amino terminal domain dimer by an induced-fit mechanism. To delineate the effect of this unique binding on GluN1/GluN2B receptor gating, we recorded steadystate currents from cell-attached and outside-out patches. At pH 7.9 in cell-attached patches, ifenprodil increased the occupancy of the long-lived shut conformations, thereby reducing the open probability of the receptor with no change in the mean open time. In addition, ifenprodil selectively affected the area of shut time constants, but not the time constants themselves. Kinetic analyses suggested that ifenprodil prevents the transition of the receptor to an open state and increases its dwell time in an intrinsically occurring closed conformation or desensitized state. We found distinct differences in the action of ifenprodil at GluN1/GluN2B in comparison with previous studies on the effect of zinc on GluN1/ GluN2A gating, which may arise due to their unique binding sites. Our data also uncover the potential pH-dependent action of ifenprodil on gating. At a low pH (pH 7.4), but not pH 7.9, ifenprodil reduces the mean open time of GluN1/GluN2B receptors, which may be responsible for its usefulness as a context-dependent inhibitor in conditions like ischemia and stroke, when the pH of the extracellular milieu becomes acidic.

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“…However, with few exceptions, there remains a lack of comprehensive glutamate receptor subunit-selectivity data for most ligands. Although the structural diversity of active ligands suggests that the binding site can accommodate different molecular scaffolds in different binding poses, few data exist with which to evaluate the idea that the compounds may share some overlapping, but not all, atomic contacts within GluN2B (Malherbe et al, 2003;Marinelli et al, 2007;Mony et al, 2009b).…”

Section: The Glun2b Amino-terminal Domain Harbors a Binding Site For mentioning

confidence: 99%

Control of Assembly and Function of Glutamate Receptors by the Amino-Terminal Domain

Hansen¹,

Furukawa²,

Traynelis³

2010

Mol Pharmacol

103

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The extracellular amino-terminal domains (ATDs) of the ionotropic glutamate receptor subunits form a semiautonomous component of all glutamate receptors that resides distal to the membrane and controls a surprisingly diverse set of receptor functions. These functions include subunit assembly, receptor trafficking, channel gating, agonist potency, and allosteric modulation. The many divergent features of the different ionotropic glutamate receptor classes and different subunits within a class may stem from differential regulation by the amino-terminal domains. The emerging knowledge of the structure and function of the amino-terminal domains reviewed here may enable targeting of this region for the therapeutic modulation of glutamatergic signaling. Toward this end, NMDA receptor antagonists that interact with the GluN2B ATD show promise in animal models of ischemia, neuropathic pain, and Parkinson's disease.

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Identification of Critical Residues in the Amino Terminal Domain of the Human NR2B Subunit Involved in the RO 25-6981 Binding Pocket

Abstract: N-Methyl-D-aspartate (NMDA) receptors play key roles in both physiological processes, particularly synaptic plasticity, and in neuropathological states such as epilepsy and acute neurodegeneration. R- (R‫,ء‬S‫-4(-␣-)

Cited by 55 publications

References 31 publications

The Micromolar Zinc-Binding Domain on the NMDA Receptor Subunit NR2B

The Micromolar Zinc-Binding Domain on the NMDA Receptor Subunit NR2B

Effect of Ifenprodil on GluN1/GluN2B N-Methyl-D-aspartate Receptor Gating

Control of Assembly and Function of Glutamate Receptors by the Amino-Terminal Domain

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