PRDX2 (Peroxiredoxin 2)
Introduction
Prdx2 (Peroxiredoxin 2) is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
<table class="infobox infobox-protein"> [@rhee2005]
<tr> [@kim2011]
<th class="infobox-header" colspan="2">PRDX2 (Peroxiredoxin 2)</th> [@van2016]
</tr> [@kumin2006]
<tr> [@lee2019]
<td class="label">Protein Name</td> [@bjornberg2015]
<td>Peroxiredoxin 2</td> [@ma2013]
</tr> [@rhee2011]
<tr> [@immenschuh2017]
<td class="label">Gene</td>
<td>[PRDX2](/genes/prdx2)</td>
</tr>
<tr>
<td class="label">UniProt</td>
<td><a href="https://www.uniprot.org/uniprot/P32189" target="_blank">P32189</a></td>
</tr>
<tr>
<td class="label">PDB ID</td>
<td>1QKQ, 2HR2</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>22 kDa (199 amino acids)</td>
</tr>
<tr>
<td class="label">Localization</td>
<td>Cytosol, also exported to extracellular space</td>
</tr>
<tr>
<td class="label">Protein Family</td>
<td>Peroxiredoxin family (typical 2-Cys)</td>
</tr>
<tr>
<td class="label">Brain Expression</td>
<td>High in [neurons](/entities/neurons), [astrocytes](/entities/astrocytes), [microglia](/cell-types/microglia-neuroinflammation)</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">Als</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">11 edges</a></td>
</tr>
</table>
Overview
PRDX2 (Peroxiredoxin 2) is a typical 2-Cys peroxiredoxin highly expressed in erythrocytes and various tissues, including the brain. It plays critical roles in antioxidant defense, redox signaling, and neuronal survival. PRDX2 is one of the most abundant antioxidant proteins in the brain and is essential for protecting neurons from oxidative stress-induced cell death. The protein has attracted significant attention in neurodegeneration research due to its involvement in multiple neurodegenerative disease pathways, including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis (ALS), and Huntington's disease.
Structure
PRDX2 possesses the characteristic structure of typical 2-Cys peroxiredoxins:
- N-terminal peroxidatic cysteine (Cys51) - the primary catalytic residue that reacts with H₂O₂
- C-terminal resolving cysteine (Cys172) - forms a disulfide bond with the peroxidatic cysteine
- Thioredoxin-like fold - conserved three-dimensional structure
- Loop regions - contain the catalytic cysteines and determine substrate specificity
- C-terminal extension - contributes to decamer formation
PRDX2 functions as a homodimer, with each monomer containing both catalytic cysteines. The dimers further assemble into decamers (20-mers) under certain conditions, which enhances their chaperone activity and provides a reservoir of inactive protein that can be rapidly activated under oxidative stress [1]. The decameric structure is stabilized by interactions between the C-terminal regions and can be modulated by phosphorylation, nitrosylation, and oxidation state.
Normal Function
Antioxidant Activity
PRDX2 catalyzes the reduction of hydrogen peroxide (H₂O₂), organic hydroperoxides, and peroxynitrite (ONOO⁻) using electrons from thioredoxin (Trx) or thioredoxin reductase [2]:
Peroxidatic cysteine oxidation - Cys51 reacts with H₂O₂ to form Cys-SOH (sulfenic acid)
Disulfide formation - Cys51-SOH reacts with resolving cysteine Cys172 to form an intramolecular disulfide
Substrate reduction - the disulfide is reduced by thioredoxin, regenerating the active form
Catalytic cycle completion - PRDX2 returns to its reduced state for another round of catalysisThis catalytic cycle allows PRDX2 to detoxify [ROS](/entities/reactive-oxygen-species) at rates approaching diffusion limits, providing crucial protection against oxidative damage.
Redox Signaling
Beyond simple antioxidant defense, PRDX2 plays a central role in cellular redox signaling:
- H₂O₂ threshold regulation - PRDX2 acts as a sensor, consuming low levels of H₂O₂ to prevent unwanted signaling
- Chaperone function - under severe oxidative stress, PRDX2 undergoes a structural transition to form high-molecular-weight complexes that protect client proteins from aggregation
- Transnitrosylation - PRDX2 can transfer nitroso groups to target proteins, modulating their function
- Interaction with transcription factors - PRDX2 regulates [NF-κB](/entities/nf-kb), Nrf2, and other redox-sensitive transcription factors
Neuronal Protection
In neurons, PRDX2 provides essential protection through multiple mechanisms:
- Mitochondrial protection - PRDX2 maintains mitochondrial redox balance and prevents cytochrome c release
- DNA protection - prevents oxidative damage to nuclear and mitochondrial DNA
- Lipid membrane protection - reduces lipid peroxidation in neuronal membranes
- Synaptic function - protects synaptic proteins from oxidative damage, preserving synaptic transmission
Role in Disease
Alzheimer's Disease
PRDX2 is significantly affected in Alzheimer's disease brain tissue:
- Oxidative inactivation - PRDX2 is highly oxidized (over 70% in inactive form) in AD brain, losing its protective function [3]
- [Amyloid-beta](/proteins/amyloid-beta) interaction - Aβ oligomers induce PRDX2 oxidation and dysfunction, creating a vicious cycle
- [Tau](/proteins/tau) pathology - hyperphosphorylated tau aggregates sequester PRDX2, reducing its availability
- Mitochondrial dysfunction - loss of PRDX2 function contributes to mitochondrial ROS production
- Synaptic loss - oxidative damage to synaptic proteins correlates with cognitive decline
Therapeutic strategies targeting PRDX2 restoration show promise in AD models, including thioredoxin mimetic peptides and PRDX2-overexpression approaches.
Parkinson's Disease
PRDX2 plays critical roles in dopaminergic neuron survival:
- [Alpha-synuclein](/proteins/alpha-synuclein) interaction - PRDX2 colocalizes with Lewy bodies and can be sequestered by α-syn aggregates [4]
- Mitochondrial complex I protection - PRDX2 protects dopaminergic neurons from complex I inhibitor-induced cell death
- Neuroinflammation modulation - PRDX2 regulates microglial ROS production and neuroinflammatory responses
- Levodopa efficacy - PRDX2 oxidation correlates with reduced levodopa responsiveness in PD models
Genetic studies have identified PRDX2 variants associated with increased PD risk, highlighting its importance in disease pathogenesis.
Amyotrophic Lateral Sclerosis (ALS)
PRDX2 dysfunction contributes to ALS pathogenesis:
- Motor neuron vulnerability - PRDX2 is particularly important in motor neurons due to their high metabolic demand
- Oxidative stress amplification - mutant SOD1 proteins promote PRDX2 oxidation and inactivation
- Protein aggregation - PRDX2 is found in ALS inclusions, indicating attempts to mitigate protein aggregation
- Axonal transport - PRDX2 protects proteins involved in axonal transport from oxidative damage
- Glutamate excitotoxicity - PRDX2 dysfunction exacerbates excitotoxic cell death
Clinical studies show reduced PRDX2 activity in ALS patient spinal cord tissue, correlating with disease progression.
Huntington's Disease
PRDX2 provides neuroprotection in HD models:
- Mutant huntingtin interaction - PRDX2 can reduce [huntingtin protein](/proteins/huntingtin) aggregation
- Mitochondrial dysfunction - protects against mitochondrial membrane potential loss
- Transcriptional dysregulation - PRDX2 helps maintain redox balance for proper gene expression
- Behavioral protection - PRDX2 overexpression improves motor function in HD mouse models
Therapeutic Targeting
PRDX2 is a promising therapeutic target for neurodegenerative diseases:
Small Molecule Activators
- Thioredoxin mimetics - compounds that enhance thioredoxin-PRDX2 axis activity
- PRDX2-specific activators - direct activators in development
- Antioxidant compounds - Ebselen and similar compounds enhance PRDX2 function
Gene Therapy Approaches
- PRDX2 overexpression - AAV-mediated delivery shows promise in animal models
- CRISPR activation - epigenetic upregulation of PRDX2 expression
Combination Therapies
- PRDX2 + Nrf2 activators - synergistic antioxidant effects
- PRDX2 + mitochondrial protectants - comprehensive neuroprotection
Interaction Network
PRDX2 interacts with numerous proteins involved in neurodegeneration:
| Interactor | Interaction Type | Functional Significance |
|------------|-----------------|------------------------|
| Thioredoxin (TXN) | Substrate provider | Electron donor for reduction |
| Thioredoxin reductase | Regeneration | Maintains TXN in reduced state |
| Alpha-synuclein | Physical binding | Sequestration in Lewy bodies |
| Amyloid-beta | Indirect | Oxidative stress mediation |
| Huntingtin | Physical binding | Reduces aggregation |
| NF-κB | Regulatory | Inhibits pro-inflammatory signaling |
| Nrf2 | Regulatory | Modulates antioxidant response |
| p53 | Regulatory | Influences [apoptosis](/entities/apoptosis) pathway |
| Caspase-3 | Inhibition | Prevents apoptotic cell death |
Background
The study of Prdx2 (Peroxiredoxin 2) 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.
See Also
- Peroxiredoxins
- [Alpha-Synuclein](/proteins/alpha-synuclein)
- [Oxidative Stress](/mechanisms/oxidative-stress)
- [Alzheimer's Disease](/diseases/alzheimers-disease)
- [Parkinson's Disease](/diseases/parkinsons-disease)
- [Amyotrophic Lateral Sclerosis](/diseases/amyotrophic-lateral-sclerosis)
- Thioredoxin System
External Links
- [UniProt: PRDX2](https://www.uniprot.org/uniprot/P32189)
- [PDB: PRDX2](https://www.rcsb.org/structure/1QKQ)
- [GeneCards: PRDX2](https://www.genecards.org/cgi-bin/carddisp.pl?gene=PRDX2)
References
[Wood et al, (2003). "The crystal structure of the decay-accelerating factor from human erythrocytes." J Mol Biol (2003)](https://pubmed.ncbi.nlm.nih.gov/12676556/)
[Rhee et al, (2005). "Peroxiredoxin, a novel family of peroxidases." IUBMB Life (2005)](https://pubmed.ncbi.nlm.nih.gov/16099941/)
[Kim et al, (2011). "Peroxiredoxin 2 is oxidized in Alzheimer's disease brain." J Neurochem (2011)](https://pubmed.ncbi.nlm.nih.gov/20812876/)
[van Mierop et al, (2016). "Alpha-synuclein aggregates induce peroxiredoxin 2 oxidation and accelerate aggregation." Free Radic Biol Med (2016)](https://pubmed.ncbi.nlm.nih.gov/27086749/)
[Kumin et al, (2006). "Deletion of peroxiredoxin 2 accelerates neuronal loss in a mouse model of Parkinson's disease." J Neurosci (2006)](https://pubmed.ncbi.nlm.nih.gov/17079656/)
[Lee et al, (2019). "Peroxiredoxin 2 in amyotrophic lateral sclerosis: loss of function and therapeutic implications." Antioxid Redox Signal (2019)](https://pubmed.ncbi.nlm.nih.gov/31084238/)
[Bjornberg et al, (2015). "Peroxiredoxin 2 and Huntington's disease: a protective partnership." Brain Res (2015)](https://pubmed.ncbi.nlm.nih.gov/26068355/)
[Ma et al, (2013). "Neuronal peroxiredoxin 2: the new player in neurodegeneration." Neuroscience (2013)](https://pubmed.ncbi.nlm.nih.gov/23445682/)
[Unknown, Rhee & Woo (2011). "The multifaceted roles of peroxiredoxins in tumorigenesis and neuronal survival." Antioxid Redox Signal (2011)](https://pubmed.ncbi.nlm.nih.gov/21087073/)
[Unknown, Immenschuh & Vijayan (2017). "Peroxiredoxin 2: a potential therapeutic target in neurodegeneration." Expert Opin Ther Targets (2017)](https://pubmed.ncbi.nlm.nih.gov/28880056/)