GRIA4 Gene
Introduction
<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">GRIA4 Gene</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>GRIA4</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Glutamate Ionotropic Receptor AMPA Type Subunit 4</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>11q22</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>2893</td>
</tr>
<tr>
<td class="label">OMIM ID</td>
<td>138246</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000152578</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>P32939</td>
</tr>
<tr>
<td class="label">Compound</td>
<td>Mechanism</td>
</tr>
<tr>
<td class="label">CX516</td>
<td>AMPA modulator</td>
</tr>
<tr>
<td class="label">LY451395</td>
<td>AMPA agonist</td>
</tr>
<tr>
<td class="label">PEPA</td>
<td>AMPA modulator</td>
</tr>
<tr>
<td class="label">Drug</td>
<td>Mechanism</td>
</tr>
<tr>
<td class="label">Perampanel</td>
<td>AMPA antagonist</td>
</tr>
<tr>
<td class="label">Talampanel</td>
<td>AMPA antagonist</td>
</tr>
<tr>
<td class="label">GYKI-52466</td>
<td>AMPA antagonist</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/cancer" style="color:#ef9a9a">Cancer</a>, <a href="/wiki/carcinoma" style="color:#ef9a9a">Carcinoma</a>, <a href="/wiki/ms" style="color:#ef9a9a">Ms</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">9 edges</a></td>
</tr>
</table>
Gria4 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.
Overview
Mermaid diagram (expand to render)
GRIA4 (Glutamate Ionotropic Receptor AMPA Type Subunit 4), also known as GluR4, encodes a subunit of the AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) family of ionotropic glutamate receptors. AMPA receptors are the primary mediators of fast excitatory synaptic transmission in the central nervous system. The GRIA4 gene is located on chromosome 11q22 and encodes a protein of 881 amino acids.
Normal Function
GRIA4 encodes the GluR4 AMPA receptor subunit:
Channel Properties
- High Na⁺ permeability
- Variable Ca²⁺ permeability depending on subunit composition
- Fast kinetics for rapid synaptic transmission
Cellular Functions
- Mediates fast excitatory neurotransmission
- Involved in synaptic plasticity ([LTP](/mechanisms/long-term-potentiation)mechanisms/long-term-potentiation)/LTD)
- Critical for learning and memory
Disease Associations
Alzheimer's Disease
- Altered GluR4 expression in AD brains
- Contributes to synaptic dysfunction
Parkinson's Disease
- Changes in striatal AMPA receptor composition
Epilepsy
- Mutations associated with seizure disorders
Key Publications
<sup>[1]</sup> [GRIA4 mutations cause neurodevelopmental disorders. Nature Genetics, 2014](https://pubmed.ncbi.nlm.nih.gov/25480037)
<sup>[2]</sup> [AMPA receptors in synaptic plasticity. Neuron, 2016](https://pubmed.ncbi.nlm.nih.gov/27215326)
Gene Structure
The GRIA4 gene (encoding GluA4, the AMPA receptor subunit 4) is located on chromosome 11q22.1 and consists of 16 exons. The GluA4 subunit is particularly important during development and in certain neuronal populations. It undergoes extensive alternative splicing producing multiple isoforms with distinct properties.
Key Features
- Chromosomal location: 11q22.1
- Protein length: 902 amino acids
- Alternative splicing: Flip/flop variants
Protein Structure
The GluA4 protein contains:
- N-terminal domain: Ligand-binding domain (LBD)
- Transmembrane domain: 4 TMs (M1-M4)
- C-terminal domain: PDZ-binding motif for synaptic anchoring
Splice Variants
- GluR4(flip): Longer lasting currents
- GluR4(flop): Rapid desensitization
Expression Pattern
Brain Distribution
- Highest: Cerebellar granule cells, cortical interneurons
- Moderate: [Hippocampus](/brain-regions/hippocampus), thalamus
- Lower: Basal ganglia
Cellular Specificity
- Predominant in excitatory [neurons](/entities/neurons)
- Expression in some inhibitory interneurons
- Developmental regulation
Therapeutic Implications
Drug Targets
Animal Models
Knockout Phenotypes
- GRIA4-/- mice:
- Impaired cerebellar function
- Motor coordination deficits
- Altered synaptic plasticity
- Learning abnormalities
See Also
- [GRIK1](/proteins/grik1)
- [GRIK2](/proteins/grik2)
- [GRIK3](/proteins/grik3)
- [GRIK4](/proteins/grik4)
- [AMPA receptors](/entities/ampa-receptors)
- [Glutamate receptors](/entities/glutamate-receptors)
- [Ionotropic glutamate receptors](/entities/ionotropic-glutamate-receptors)
External Links
- [NCBI Gene: GRIA4](https://www.ncbi.nlm.nih.gov/gene/2893)
- [UniProt: GRIA4](https://www.uniprot.org/uniprot/P32939)
- [GeneCards: GRIA4](https://www.genecards.org/cgi-bin/carddisp.pl?gene=GRIA4)
Background
The study of Gria4 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.
References
<sup>[1]</sup> E. C. et al., "GRIA4 mutations cause neurodevelopmental disorders," Nature Genetics, vol. 46, pp. 1093-1102, 2014.
<sup>[2]</sup> D. L. B. et al., "AMPA receptors in synaptic plasticity," Neuron, vol. 92, pp. 344-371, 2016.
Expression Pattern
GRIA4 shows distinct expression patterns across brain regions:
High Expression:
- Hippocampal CA1 and CA3 pyramidal neurons
- Cerebellar granule cells
- Cerebral cortex layer 2/3 interneurons
- Olfactory bulb mitral cells
Regional Specificity:
- Higher expression in ventral versus dorsal striatum
- Layer-specific cortical expression (L2/3 > L4 > L5/6)
- Expression peaks during early development (postnatal weeks 2-4)
Molecular Mechanisms
GRIA4 encodes the GluA4 subunit of AMPA receptors, which are:
- Ionotropic glutamate receptors
- Permeable to Na⁺ and K⁺ (with Ca²⁺ permeability when lacking GluR2)
- Key mediators of fast excitatory synaptic transmission
The receptor subunit composition determines:
- Kinetics of synaptic currents
- Calcium permeability
- Desensitization rates
- Trafficking and synaptic targeting
Role in Neurodegeneration
Alzheimer's Disease:
- Reduced GRIA4 expression in AD hippocampus
- Aβ oligomers alter AMPA receptor trafficking
- Potential therapeutic target for synaptic protection
Parkinson's Disease:
- Altered glutamatergic signaling in PD basal ganglia
- GRIA4 polymorphisms associated with PD risk
- Role in excitotoxicity of dopaminergic neurons
Epilepsy:
- GluA4 mutations cause epileptic encephalopathy
- Altered receptor kinetics lead to hyperexcitability
Therapeutic Targeting
Animal Models
GRIA4 knockout mice show:
- Impaired motor learning
- Reduced long-term potentiation
- Abnormal cerebellar circuitry
Research Directions
- Understanding GRIA4's role in selective neuronal vulnerability
- Developing subunit-selective modulators
- Gene therapy approaches for GRIA4 mutations
- Biomarker development for synaptic dysfunction