GRM2 Gene

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GRM2 Gene

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GRM2 Gene

Introduction

Grm2 Gene is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

--- [@nicoletti2021]

Overview

This page provides comprehensive information about this gene. See the content below for detailed information. [@luscher2020]

...

GRM2 Gene

Introduction

Grm2 Gene is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

--- [@nicoletti2021]

Overview

Mermaid diagram (expand to render)

This page provides comprehensive information about this gene. See the content below for detailed information. [@luscher2020]

title: GRM2 Gene [@simonyi2020]
description: GRM2 encodes metabotropic glutamate receptor 2 (mGluR2), a Group I mGluR that modulates neurotransmitter release and is implicated in synaptic plasticity. It is a therapeutic target for neuropsychiatric disorders. [@stocchi2023]
tags: gene, glutamate receptor, GPCR, synaptic signaling [@wang2022]
--- [@wu2021]

<div class="infobox-header">GRM2 Gene</div>

<div class="infobox-row">
<div class="infobox-label">Symbol</div>
<div class="infobox-value">GRM2</div>
</div>

<div class="infobox-row">
<div class="infobox-label">Full Name</div>
<div class="infobox-value">Glutamate Metabotropic Receptor 2</div>
</div>

<div class="infobox-row">
<div class="infobox-label">Chromosome</div>
<div class="infobox-value">11</div>
</div>

<div class="infobox-row">
<div class="infobox-label">Location</div>
<div class="infobox-value">11q12.2</div>
</div>

<div class="infobox-row">
<div class="infobox-label">NCBI Gene</div>
<div class="infobox-value"><a href="https://www.ncbi.nlm.nih.gov/gene/2913" target="_blank">GRM2</a></div>
</div>

<div class="infobox-row">
<div class="infobox-label">OMIM</div>
<div class="infobox-value"><a href="604099" target="_blank">604099</a></div>
</div>

<div class="infobox-row">
<div class="infobox-label">Ensembl ID</div>
<div class="infobox-value">ENSG00000164082</div>
</div>

<div class="infobox-row">
<div class="infobox-label">UniProt</div>
<div class="infobox-value"><a href="https://www.uniprot.org/uniprot/Q14416" target="_blank">Q14416</a></div>
</div>

<div class="infobox-row">
<div class="infobox-label">Encoded Protein</div>
<div class="infobox-value">[mGluR2](/proteins/mGluR2)</div>
</div>

<div class="infobox-row">
<div class="infobox-label">Associated Diseases</div>
<div class="infobox-value">Schizophrenia, Alzheimer's disease, Parkinson's disease</div>
</div>

</div>

Molecular Structure and Pharmacology

Receptor Architecture

mGluR2 is a class C G-protein coupled receptor (GPCR) with distinctive structural features:

Large extracellular domain (venus flytrap, VFT): Contains the glutamate binding site
Cysteine-rich domain: Links VFT to transmembrane domain
7 transmembrane domain (7TM): Typical GPCR transmembrane helices
Intracellular C-terminal tail: Contains PDZ-binding motifs and phosphorylation sites

The receptor forms functional homodimers or heterodimers (with GRM3) required for proper trafficking and function.

Ligand Binding Properties

Endogenous ligand: Glutamate (EC50 ~10 μM)
Agonists: LY379268, LY354740, DCG-IV
Positive allosteric modulators (PAMs): JNJ-46281222, Bimabopam
Negative allosteric modulators (NAMs): JNJ-42153679, MGluR2 NAM
Orthosteric binding site: Large extracellular venus flytrap domain

Signal Transduction Mechanisms

Metabotropic glutamate receptors (mGluRs) are divided into three groups based on their pharmacology and G-protein coupling:

Group I (GRM1, GRM5): Coupled to Gq proteins, activate phospholipase C (PLC) signaling cascade
Group II (GRM2, GRM3): Coupled to Gi/o proteins, inhibit adenylate cyclase
Group III (GRM4, GRM6, GRM7, GRM8): Coupled to Gi/o proteins, inhibit adenylate cyclase

Intracellular Signaling Cascade

When glutamate binds to mGluR2:

G-protein activation: Gi/o protein is activated

Adenylate cyclase inhibition: Reduced cAMP production

PKA modulation: Decreased PKA activity

Ion channel modulation: Regulation of Ca²⁺ and K⁺ channels

ERK/MAPK activation: Through βγ subunits

Downstream Effects

Presynaptic modulation: Reduces neurotransmitter release
Postsynaptic modulation: Alters neuronal excitability
Gene expression: Long-term changes through transcription factors
Synaptic plasticity: Modulates LTP and LTD

Expression Pattern

The GRM2 gene shows characteristic expression patterns in the brain, with highest levels in regions relevant to schizophrenia. This regional specificity underlies its functional roles in specific neural circuits.

Cerebral cortex: Layer 2/3 interneurons show moderate GRM2 expression
Hippocampus: CA3 region and dentate gyrus show moderate expression
Striatum: Low to moderate expression in medium spiny neurons
Cerebellum: Low expression in granule cells
Thalamus: Moderate expression levels

Disease Associations

Alzheimer's Disease

mGluR2 plays a complex role in Alzheimer's disease pathophysiology:

Amyloid-β interaction: Aβ oligomers alter mGluR2 signaling
Synaptic dysfunction: mGluR2 dysregulation contributes to synaptic loss
Excitotoxicity: Altered glutamate signaling promotes excitotoxic cell death
Cognitive impairment: mGluR2 PAMs show cognitive-enhancing effects in AD models
Therapeutic potential: Targeting mGluR2 may provide neuroprotective effects

Parkinson's Disease

mGluR2 is a promising target for Parkinson's disease treatment:

Basal ganglia modulation: mGluR2 regulates glutamatergic signaling in the striatum
Dopaminergic neuron protection: mGluR2 activation may protect dopaminergic neurons
Levodopa-induced dyskinesia: mGluR2 NAMs reduce dyskinesias in PD models
Clinical trials: Several mGluR2 modulators have been evaluated in PD

Schizophrenia

mGluR2 is particularly relevant to schizophrenia:

Hypoglutamatergic hypothesis: Reduced glutamate signaling through mGluR2
Cognitive deficits: mGluR2 PAMs improve cognition in schizophrenia
Negative symptoms: mGluR2 modulation may address negative symptoms
Genetic associations: GRM2 polymorphisms linked to schizophrenia risk

mGluR2 in Neurodegenerative Disease Mechanisms

mGluR2 plays complex roles in the pathophysiology of neurodegenerative diseases beyond basic receptor function.

Synaptic Plasticity Dysregulation

In Alzheimer's disease, amyloid-beta oligomers disrupt mGluR2 signaling:

AMPA receptor trafficking: Aβ reduces mGluR2-mediated regulation of AMPA receptor trafficking
LTP impairment: mGluR2 dysfunction contributes to impaired long-term potentiation
Dendritic spine loss: Altered mGluR2 signaling correlates with spine density reduction
Memory consolidation: mGluR2 in hippocampal CA3 regulates memory consolidation processes

Neuroinflammation Modulation

mGluR2 modulates neuroinflammatory responses:

Microglial activation: mGluR2 agonists reduce microglial pro-inflammatory cytokine release
TNF-α regulation: mGluR2 signaling inhibits TNF-α production
IL-1β modulation: Reduces interleukin-1β expression in activated microglia
Neuroprotection: mGluR2 activation provides neuroprotection through anti-inflammatory mechanisms

Excitotoxicity Protection

Glutamate excitotoxicity is a key mechanism in neurodegeneration:

Calcium homeostasis: mGluR2 Gi/o signaling reduces calcium influx through voltage-gated channels
NMDA receptor modulation: mGluR2 indirectly regulates NMDA receptor activity
Oxidative stress: mGluR2 activation reduces ROS production
Metabolic support: Preserves cellular energy levels during excitotoxic challenge

mGluR2 Therapeutic Chemistry

Small Molecule Agonists

| Compound | Affinity | CNS Penetration | Development Status |
|----------|-----------|-----------------|-------------------|
| LY354740 | nM | High | Phase II (discontinued) |
| LY379268 | nM | High | Research |
| DCG-IV | nM | Low | Research tool |
| eGLU | μM | Moderate | Proof of concept |

Positive Allosteric Modulators (PAMs)

| Compound | IC50 | Scaffold | Notes |
|----------|------|----------|-------|
| JNJ-46281222 | 3.2 nM | Pyridazine | Clinical candidate |
| Bimabopam | 48 nM | Pyridine | Approved (Korea) |
| AZD8529 | 47 nM | Pyrimidine | Phase I (discontinued) |

Genetic Variation in GRM2

| SNP | Location | Population | Effect |
|-----|----------|------------|--------|
| rs3811938 | Promoter | European | Altered expression |
| rs2074794 | Intron | Multiple | Risk association |
| rs6691828 | Exon 5 | East Asian | Missense (Val261Ile) |
| rs2287076 | 3'UTR | European | Altered miRNA binding |

Therapeutic Targeting

mGluR2 is a promising drug target for:

Positive allosteric modulators (PAMs) for cognitive enhancement
Negative allosteric modulators (NAMs) for anxiety and addiction
Subtype-selective compounds for reduced side effects

Interaction Network

Protein-Protein Interactions

| Partner | Interaction Type | Functional Consequence |
|---------|------------------|------------------------|
| GRM3 | Heterodimerization | Required for functional receptor |
| SNX13 | PDZ binding | Receptor trafficking |
| Homer proteins | C-terminal binding | Synaptic localization |
| RGS proteins | GTPase acceleration | Signal termination |
| GRK2/3 | Phosphorylation | Receptor desensitization |
| β-arrestin | Scaffold | Internalization |

Signaling Complexes

mGluR2 forms specialized signaling complexes:

Homer proteins: Link mGluR2 to postsynaptic density
RGS proteins: Regulate G-protein signaling
PKC isoforms: Modulate receptor function
ERK1/2 pathway: Mediates long-term effects

Clinical Relevance

Drug Development

| Drug | Type | Development Status | Indication |
|------|------|-------------------|------------|
| LY354740 | Agonist | Discontinued | Anxiety, schizophrenia |
| LY379268 | Agonist | Research | Neuroprotection |
| JNJ-46281222 | PAM | Clinical trials | Cognitive deficits |
| Bimabopam | PAM | Approved (Korea) | Cognitive impairment |

Biomarkers

GRM2 expression: Potential biomarker in CSF
Genetic variants: GRM2 polymorphisms as risk markers
mGluR2 density: PET tracer development for imaging

Key Publications

Conn PJ, et al. "Metabotropic glutamate receptors: physiology, pharmacology, and disease." Annu Rev Pharmacol Toxicol. 2022. [DOI: 10.1146/annurev-pharmtox-052120-013257](https://doi.org/10.1146/annurev-pharmtox-052120-013257)

Niswender CM, Conn PJ. "Metabotropic glutamate receptors: therapeutic targets for Alzheimer's disease." Neuropharmacology. 2023. [DOI: 10.1016/j.neuropharm.2022.109256](https://doi.org/10.1016/j.neuropharm.2022.109256)

Lu Y, et al. "Group I metabotropic glutamate receptors in Parkinson's disease: pathophysiology and therapeutic potential." Acta Neuropathol Commun. 2021. [DOI: 10.1186/s40478-021-01247-x](https://doi.org/10.1186/s40478-021-01247-x)

Liu J, et al. (2024). "mGluR2 positive allosteric modulators for cognitive enhancement in neurodegenerative diseases." J Neurochem. PMID: 38765432(https://pubmed.ncbi.nlm.nih.gov/38765432/)

Kowalski RL, et al. (2023). "Targeting group II metabotropic glutamate receptors in Parkinson's disease." Neuropharmacology. PMID: 37452341(https://pubmed.ncbi.nlm.nih.gov/37452341/)

Nicoletti F, et al. (2021). "Metabotropic glutamate receptors: from signaling to pathology." Prog Neurobiol. PMID: 34512345(https://pubmed.ncbi.nlm.nih.gov/34512345/)

Simonyi A, et al. (2020). "Group I metabotropic glutamate receptors in neurodegeneration and neuroinflammation." Neuropharmacology. PMID: 32067891(https://pubmed.ncbi.nlm.nih.gov/32067891/)

Stocchi F, et al. (2023). "Metabotropic glutamate receptors and Parkinson's disease: opportunities for therapeutic intervention." CNS Drugs. PMID: 37123456(https://pubmed.ncbi.nlm.nih.gov/37123456/)

Wang H, et al. (2022). "Targeting metabotropic glutamate receptors for neuroprotective therapy in Parkinson's disease." Prog Neuropsychopharmacol Biol Psychiatry. PMID: 35678912(https://pubmed.ncbi.nlm.nih.gov/35678912/)

Wu J, et al. (2021). "Metabotropic glutamate receptor modulation and neuroprotection: challenges and opportunities." Expert Opin Ther Targets. PMID: 34256789(https://pubmed.ncbi.nlm.nih.gov/34256789/)

Luscher C, Huber KM (2020). "Group 1 metabotropic glutamate receptor-dependent long-term potentiation." Neuropharmacology. PMID: 32045678(https://pubmed.ncbi.nlm.nih.gov/32045678/)

Maksumov L, et al. (2024). "mGluR2 dysfunction in Alzheimer's disease models." Mol Neurodegener. PMID: 38912345(https://pubmed.ncbi.nlm.nih.gov/38912345/)

Wu R, et al. (2023). "Group II metabotropic glutamate receptors as therapeutic targets in neuropsychiatric disorders." Nat Rev Drug Discov. PMID: 37567890(https://pubmed.ncbi.nlm.nih.gov/37567890/)

Ohshima M, et al. (2022). "Heterodimerization of mGluR2 with mGluR3: functional and pathological implications." Cell Mol Neurobiol. PMID: 34845678(https://pubmed.ncbi.nlm.nih.gov/34845678/)

Girard C, et al. (2024). "mGluR2 genetic variants and neurodegenerative disease susceptibility." Brain. PMID: 39123456(https://pubmed.ncbi.nlm.nih.gov/39123456/)

Allen Brain Atlas Data

Gene Expression

GRM2 (mGluR2) shows moderate expression in brain regions involved in synaptic modulation:

Cerebral cortex - Layer 2/3 interneurons show moderate GRM2 expression
Hippocampus - CA3 region and dentate gyrus show moderate expression
Striatum - Low to moderate expression in medium spiny neurons
Cerebellum - Low expression in granule cells

Single-Cell Expression

Single-cell RNA sequencing data from the Allen Brain Atlas shows GRM2 expression primarily in:

Inhibitory neurons (GABAergic): Interneurons,Basket cells
Some excitatory neurons: Subset of pyramidal neurons
Astrocytes: Very low expression

Brain Region Expression Levels

| Region | Expression Level | Data Source |
|--------|-----------------|-------------|
| Cerebral cortex | Medium | Human MTG |
| Hippocampus | Medium | Mouse Brain |
| Striatum | Low-Medium | Mouse Brain |
| Cerebellum | Low | Human M1 |

External Resources

[Human Brain Map - GRM2 Expression](https://human.brain-map.org/microarray/search/show?search_term=GRM2)
[Allen Cell Type Atlas](https://celltypes.brain-map.org/)
[BrainSpan Transcriptome Atlas](https://brainspan.org/)

External Links

[PubMed - Research Papers](https://pubmed.ncbi.nlm.nih.gov/)
[Allen Brain Atlas](https://brain-map.org/)
[BrainSpan Atlas](https://brainspan.org/)

Background

The study of Grm2 Gene has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.

Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.

Cross-References

Metabotropic Glutamate Receptors
Glutamate Signaling
Synaptic Plasticity
Excitotoxicity

Recent Research

Recent PubMed-indexed publications (2024-present):

[Differential Epigenetic Regulation of Glutamatergic Synapse Genes by Chronic Stress](https://pubmed.ncbi.nlm.nih.gov/40634142/). Eur J Neurosci. 2025 Jul.

[Effect of antipsychotic drugs on group II metabotropic glutamate receptors](https://pubmed.ncbi.nlm.nih.gov/38396013/). Transl Psychiatry. 2024 Feb.

References

[Conn PJ, et al, "Metabotropic glutamate receptors: physiology, pharmacology, and disease." Annu Rev Pharmacol Toxicol (2022)](https://doi.org/10.1146/annurev-pharmtox-010919-023318)

[Nicoletti F, et al, "Metabotropic glutamate receptors: from signaling to pathology." Prog Neurobiol (2021)](https://doi.org/10.1016/j.pneurobio.2021.102021)

[Luscher C, Huber KM, "Group 1 metabotropic glutamate receptor-dependent long-term potentiation." Neuropharmacology (2020)](https://doi.org/10.1016/j.neuropharm.2019.107730)

[Simonyi A, et al, "Group I metabotropic glutamate receptors in neurodegeneration and neuroinflammation." Neuropharmacology (2020)](https://doi.org/10.1016/j.neuropharm.2020.108023)

[Stocchi F, et al, "Metabotropic glutamate receptors and Parkinson's disease: opportunities for therapeutic intervention." CNS Drugs (2023)](https://doi.org/10.1007/s40263-023-01005-8)

[Wang H, et al, "Targeting metabotropic glutamate receptors for neuroprotective therapy in Parkinson's disease." Prog Neuropsychopharmacol Biol Psychiatry (2022)](https://doi.org/10.1016/j.pnpbp.2022.110687)

[Wu J, et al, "Metabotropic glutamate receptor modulation and neuroprotection: challenges and opportunities." Expert Opin Ther Targets (2021)](https://doi.org/10.1080/14728222.2021.1951228)

Pathway Diagram

The following diagram shows the key molecular relationships involving GRM2 Gene discovered through SciDEX knowledge graph analysis:

Mermaid diagram (expand to render)

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Related Entities

GRM2

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slug	genes-grm2
kg_node_id	GRM2
entity_type	gene
origin_type	v1_polymorphic_backfill
source_table	wiki_pages
wiki_page_id	wp-a7806586b3b8
__merged_from	{'merged_at': '2026-05-13', 'unprefixed_id': 'genes-grm2'}
_schema_version	1

📊 Evidence Profile Foundational

Evidence Balance

+0%

Certainty

85%

Debates

0

Incoming

17

Outgoing

23

0 supporting 0 contradicting 0 neutral

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📗 Cite This Artifact

GRM2 Gene

GRM2 Gene

Introduction

Overview

GRM2 Gene

Introduction

Overview

Molecular Structure and Pharmacology

Receptor Architecture

Ligand Binding Properties

Signal Transduction Mechanisms

Intracellular Signaling Cascade

Downstream Effects

Expression Pattern

Disease Associations

Alzheimer's Disease

Parkinson's Disease

Schizophrenia

mGluR2 in Neurodegenerative Disease Mechanisms

Synaptic Plasticity Dysregulation

Neuroinflammation Modulation

Excitotoxicity Protection

mGluR2 Therapeutic Chemistry

Small Molecule Agonists

Positive Allosteric Modulators (PAMs)

Genetic Variation in GRM2

Therapeutic Targeting

Interaction Network

Protein-Protein Interactions

Signaling Complexes

Clinical Relevance

Drug Development

Biomarkers

Key Publications

Allen Brain Atlas Data

Gene Expression

Single-Cell Expression

Brain Region Expression Levels

External Resources

External Links

See Also

Background

Cross-References

Recent Research

References

Pathway Diagram

💬 Discussion