P2RX3 Gene

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P2RX3 Gene

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">P2RX3 Gene</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td><strong>P2RX3</strong></td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>P2RX3</td>
</tr>
<tr>
<td class="label">Type</td>
<td>Gene</td>
</tr>
<tr>
<td class="label">NCBI</td>
<td><a href="https://www.ncbi.nlm.nih.gov/gene/?term=P2RX3" target="_blank">Search NCBI</a></td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/aging" style="color:#ef9a9a">Aging</a>, <a href="/wiki/inflammation" style="color:#ef9a9a">Inflammation</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">31 edges</a></td>
</tr>
</table>

Introduction

P2Rx3 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

...

P2RX3 Gene

Introduction

P2Rx3 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)

The P2RX3 (Purinergic Receptor P2X Ligand-Gated Ion Channel 3) gene encodes a member of the P2X family of ATP-gated ion channels. P2X3 receptors are primarily expressed in sensory [neurons](/entities/neurons) and play crucial roles in pain sensation, taste transduction, and autonomic functions["@burnstock2018"].

Gene Information

Official Symbol: P2RX3
Official Full Name: Purinergic Receptor P2X Ligand-Gated Ion Channel 3
Chromosomal Location: 11q12.1
Gene ID: 5024
Protein: P2X3 Receptor
UniProt: P56378
OMIM: 602243

Protein Structure

P2X3 receptors are trimeric ion channels composed of three identical subunits. Each subunit contains:

N-terminal extracellular domain (~290 residues): Contains the ATP-binding site
Two transmembrane domains (TM1 and TM2): Form the ion pore
C-terminal intracellular domain (~30 residues): Important for channel regulation

The trimeric assembly creates a central pore that is permeable to Na⁺, K⁺, and Ca²⁺ ions. Each subunit contributes to the ATP-binding pocket located at the subunit interface[@north2020].

ATP-Binding Mechanism

The ATP-binding site is formed by:

Orphan sites: Residues on adjacent subunits
Phosphate-binding loop: Basic residues for ATP recognition
Adenine recognition pocket: Hydrophobic residues for base binding

Channel Gating

P2X3 receptors exhibit unique gating properties:

Activation

Rapid response: Channel opens within milliseconds of ATP binding
Low EC₅₀: High sensitivity to ATP (EC₅₀ ~1 μM)
Voltage independence: Gating is largely voltage-independent

Desensitization

Fast desensitization: Current decays within 100-200 ms
Recovery: Slow recovery from desensitization (seconds)
Cysteine-rich domain: Critical for desensitization kinetics

Resensitization

ATP removal: Required for recovery
Phosphorylation: PKC can modulate desensitization rates

Molecular Function

P2RX3 encodes an ATP-gated ion channel:

Ion channel: Rapidly permeable to Na⁺, K⁺, and Ca²⁺
Fast desensitization: Quick response to ATP
Pain signaling: Critical for nociceptor activation
Taste transduction: Type III taste cells require P2X3
Hetero-trimeric: Often forms heteromers (especially with P2X2)

P2X2/3 Heteromeric Channels

P2X3 subunits readily form heterotrimeric channels with P2X2:

Distinct properties: Different gating and pharmacology
Slower desensitization: More sustained currents
ATP sensitivity: Similar EC₅₀ values
Distribution: Co-expressed in sensory neurons

Expression Pattern

P2RX3 is primarily expressed in sensory systems:

Peripheral Nervous System

Dorsal root ganglion (DRG): Small-diameter sensory neurons
Trigeminal ganglion: Craniofacial pain receptors
Nodose ganglion: Visceral sensory information
Enteric nervous system: Gut sensory signaling

Central Nervous System

Spinal cord dorsal horn: Pain transmission
Brainstem: Autonomic integration
Hippocampal interneurons: Modulatory role

Specialized Tissues

Taste buds: Type III receptor cells
Airway epithelia: Chemosensing
Urinary bladder: P2X3 in afferent signaling

Disease Associations

Chronic Pain

P2X3 is a major contributor to chronic pain states[@ford2019]:

Neuropathic Pain

Nerve injury upregulates P2X3 expression
Contributes to allodynia and hyperalgesia
ATP release from damaged cells activates P2X3

Inflammatory Pain

P2X3 sensitization via inflammatory mediators
Cytokine modulation of channel function
Therapeutic target for inflammatory conditions

Migraine

Trigeminal P2X3 involvement
CGRP-P2X3 interactions
Meningeal nociceptor activation

Visceral Pain

Gut-pain signaling via P2X3
Irritable bowel syndrome (IBS)
Bladder pain syndrome

Taste Disorders

P2X3 is essential for sour taste transduction[@vandenbeuch2015]:

Ageusia: Complete loss of taste
Dysgeusia: Distorted taste perception
Type III cells: Require P2X3 for signaling

Alzheimer's Disease

P2X3 alterations in AD:

Sensory signaling changes: Altered pain perception
Calcium dysregulation: P2X3-mediated Ca²⁺ influx
Therapeutic potential: P2X3 as drug target
Neuroinflammation: ATP-P2X3 signaling in glia

Parkinson's Disease

P2X3 in PD:

Non-motor symptoms: Sensory dysfunction
Olfactory impairment: Possible role in smell loss
Pain: PD-related pain mechanisms

Therapeutic Targeting

P2X3 is a major drug target, especially for pain[@chessell2005]:

Antagonists

First-Generation

PPADS: Non-selective P2 antagonist
Suramin: Broad P2X antagonist

Selective Antagonists

A-317491: First selective P2X3 antagonist
AF-353 (RO-4): Highly selective
AF-942: Improved potency
BL-5529: Clinical candidate

Clinical Development

Chronic cough: Gefapixant (BL-4740) — FDA approved
Overactive bladder: Resiniferatoxin trials
Neuropathic pain: Phase II trials ongoing
Migraine: P2X3-targeting approaches

Advantages of P2X3 Targeting

Peripheral targets: Reduced CNS side effects
Non-opioid mechanism: No addiction potential
Disease modification: May address underlying pathology

Animal Models

P2RX3 knockout mice have provided crucial insights:

Pain responses: Deficient inflammatory and neuropathic pain
Taste: Impaired sour taste perception
Viability: Viable and fertile
Behavior: Normal development and locomotion

Interaction Network

P2X3 interacts with various proteins and signaling pathways:

Channel Partners

P2X2: Heteromeric channel formation
P2X5: Possible heteromers in some tissues
P2X7: Cross-talk in pain signaling

Signaling Molecules

PKC: Modulates desensitization
ATP: Primary agonist
Adenosine: Antagonistic effects

Disease Proteins

CGRP: Co-release in trigeminal system
TRPV1: Functional interactions
Sodium channels: Nav1.7, Nav1.8

Background

The study of P2Rx3 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.

External Links

[NCBI Gene: P2RX3](https://www.ncbi.nlm.nih.gov/gene/5024)
[UniProt: P56378](https://www.uniprot.org/uniprot/P56378)
[OMIM: 602243](https://www.omim.org/entry/602243)
[Wikipedia: P2RX3](https://en.wikipedia.org/wiki/P2RX3)

References

[Burnstock G, (2018) (2018)](https://pubmed.ncbi.nlm.nih.gov/29374161/)

[North RA, Jarvis MF, (2020) (2020)](https://pubmed.ncbi.nlm.nih.gov/32467642/)

[Ford AP, (2019) (2019)](https://pubmed.ncbi.nlm.nih.gov/31267783/)

[Vandenbeuch A, Kinnamon SC, (2015) (2015)](https://pubmed.ncbi.nlm.nih.gov/26206941/)

[Chessell IP, et al, (2005) (2005)](https://pubmed.ncbi.nlm.nih.gov/15777864/)

Pathway Diagram

The following diagram shows the key molecular relationships involving P2RX3 Gene discovered through SciDEX knowledge graph analysis:

Mermaid diagram (expand to render)

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P2RX3 Gene

P2RX3 Gene

Introduction

Overview

P2RX3 Gene

Introduction

Overview

Gene Information

Protein Structure

ATP-Binding Mechanism

Channel Gating

Activation

Desensitization

Resensitization

Molecular Function

P2X2/3 Heteromeric Channels

Expression Pattern

Peripheral Nervous System

Central Nervous System

Specialized Tissues

Disease Associations

Chronic Pain

Taste Disorders

Alzheimer's Disease

Parkinson's Disease

Therapeutic Targeting

Antagonists

Clinical Development

Advantages of P2X3 Targeting

Animal Models

Interaction Network

Channel Partners

Signaling Molecules

Disease Proteins

Background

See Also

External Links

References

Pathway Diagram