GRIA4 Protein - Glutamate Receptor AMPA Type Subunit 4

GRIA4 Protein - Glutamate Receptor AMPA Type Subunit 4

Introduction

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">GRIA4 Protein - Glutamate Receptor AMPA Type Subunit 4</th>
</tr>
<tr>
<td class="label">Protein Name</td>
<td>Glutamate receptor 4</td>
</tr>
<tr>
<td class="label">Gene</td>
<td>GRIA4</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>P35070</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~101 kDa</td>
</tr>
<tr>
<td class="label">Subcellular Localization</td>
<td>Plasma membrane, postsynaptic density</td>
</tr>
<tr>
<td class="label">Protein Family</td>
<td>Ionotropic glutamate receptor (AMPA)</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 Protein Glutamate Receptor Ampa Type Subunit 4 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

GRIA4 Protein - Glutamate Receptor AMPA Type Subunit 4

Introduction

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">GRIA4 Protein - Glutamate Receptor AMPA Type Subunit 4</th>
</tr>
<tr>
<td class="label">Protein Name</td>
<td>Glutamate receptor 4</td>
</tr>
<tr>
<td class="label">Gene</td>
<td>GRIA4</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>P35070</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~101 kDa</td>
</tr>
<tr>
<td class="label">Subcellular Localization</td>
<td>Plasma membrane, postsynaptic density</td>
</tr>
<tr>
<td class="label">Protein Family</td>
<td>Ionotropic glutamate receptor (AMPA)</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 Protein Glutamate Receptor Ampa Type Subunit 4 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

GRIA4 Protein (GluR4/AMPA receptor subunit 4) is encoded by the GRIA4 gene. It is a subunit of the AMPA-type glutamate receptors, which mediate the majority of fast excitatory synaptic transmission in the brain. [@hollmann1994]

Protein Information

Structure

AMPA receptors are tetrameric ion channels composed of four subunits (GRIA1-4):

• N-terminal domain - Ligand binding (LBD)
• Transmembrane domain - Three segments (M1, M3, M4)
• C-terminal domain - Intracellular, PDZ-binding motifs
• Flip/flop alternative splicing - Determines desensitization kinetics

Normal Function

Synaptic Transmission

• Mediates fast excitatory postsynaptic currents
• Primary mediator of rapid synaptic signaling
• Determines EPSP kinetics

Synaptic Plasticity

• Essential for [LTP](/mechanisms/long-term-potentiation) and LTD
• Activity-dependent trafficking
• Homeostatic scaling

Learning and Memory

• Critical for cognitive function
• [Long-term potentiation](/mechanisms/long-term-potentiation) mechanism

Role in Disease

Alzheimer's Disease

• Altered AMPA receptor expression
• [Aβ](/proteins/amyloid-beta) affects trafficking
• Synaptic receptor loss correlates with cognitive decline

Parkinson's Disease

• AMPA receptor alterations in models
• Therapeutic target potential

Epilepsy

• GRIA4 mutations cause epileptic encephalopathy
• Aberrant trafficking in seizures
• AMPA receptor antagonists as anticonvulsants

Stroke/Ischemia

• Excitotoxicity via AMPA receptors
• Neuroprotective strategies

Therapeutic Targeting

Approved Drugs

• Perampanel - FDA-approved AMPA antagonist for epilepsy

Under Development

• AMPA receptor modulators for neuroprotection
• Positive allosteric modulators for cognitive enhancement

Molecular Mechanisms

Receptor Assembly and Trafficking

GRIA4 assembles with other AMPA receptor subunits (GRIA1, GRIA2, GRIA3) to form functional tetrameric receptors. The composition determines:

• Channel properties: Conductance, kinetics, calcium permeability
• Pharmacology: Agonist and antagonist sensitivity
• Trafficking: Forward trafficking to synapses
• Synaptic plasticity: LTP and LTD mechanisms

• High calcium permeability (when lacking GRIA2 edited form)
• Slow desensitization kinetics
• Expression during critical periods of synaptic development

Synaptic Plasticity

GRIA4 plays a crucial role in synaptic plasticity:

[Long-Term Potentiation](/mechanisms/long-term-potentiation) (LTP)

• NMDAR activation triggers Ca²⁺ influx
• CaMKII phosphorylates AMPA receptors
• GRIA4 insertion into synaptic membrane
• Enhanced synaptic strength

• AMPA receptor internalization
• Reduced synaptic GRIA4
• Weakened synaptic transmission

Calcium Signaling

Unlike GRIA2-containing receptors, GRIA4 homomers and heteromers are calcium-permeable:

• Triggers intracellular signaling cascades
• Activates calcium-dependent enzymes
• Can lead to excitotoxicity if dysregulated

Brain Region Distribution

GRIA4 shows region-specific expression:

• [Hippocampus](/brain-regions/hippocampus): CA1-CA3 regions, dentate gyrus granule cells
• Cerebral [cortex](/brain-regions/cortex): Layer 2/3 pyramidal [neurons](/entities/neurons)
• Cerebellum: Granule cells
• Basal ganglia: Medium spiny neurons

Disease Mechanisms

Alzheimer's Disease

• [Aβ](/proteins/amyloid-beta) oligomers reduce GRIA4 surface expression
• Early loss of AMPA receptor-mediated transmission
• Correlation with cognitive decline
• Therapeutic target for synaptic protection

Parkinson's Disease

• Altered AMPA receptor subunit composition in striatum
• Dysregulated glutamatergic signaling
• Potential target for motor complications

Epileptic Encephalopathy

• De novo GRIA4 mutations identified in patients
• Dominant-negative effects on receptor function
• Causes early-onset seizures and developmental delay

Stroke and Traumatic Brain Injury

• Excitotoxicity through calcium-permeable AMPA receptors
• Therapeutic potential of AMPA antagonists
• Neuroprotective strategies

Therapeutic Development

Current Therapies

• Perampanel: Non-competitive AMPA antagonist (FDA-approved for epilepsy)
• Lacosamide: Enhances sodium channel slow inactivation

Investigational Approaches

• Positive allosteric modulators: Enhance receptor function for cognitive enhancement
• Calcium-permeable AMPA receptor antagonists: Neuroprotection in stroke/TBI
• GRIA4-selective compounds: Targeted therapy for specific conditions

Research Methods

Electrophysiology

• Whole-cell patch-clamp recordings
• Paired-pulse facilitation measurements
• LTP/LTD induction protocols

Molecular Biology

• siRNA knockdown in neurons
• CRISPR gene editing
• Fluorescent protein tagging

Imaging

• Live-cell imaging of receptor trafficking
• Super-resolution microscopy
• Electron microscopy for synaptic localization

Background

The study of Gria4 Protein Glutamate Receptor Ampa Type Subunit 4 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.

Key Publications

See Also

• GRIA4 Gen- Glutamate Receptors
• AMPA Receptors
• Ionotropic Glutamate Receptors
• [Synaptic Transmission](/mechanisms/synaptic-dysfunction) [Excitotoxicity](/mechanisms/excitotoxicity-neurodegeneration)

External Links

• [UniProt: P35070](https://www.uniprot.org/uniprot/P35070)
• [PDB Structure](https://www.rcsb.org/)

References