NOX2/CYBB (NADPH Oxidase 2)

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NOX2/CYBB (NADPH Oxidase 2)

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NOX2/CYBB (NADPH Oxidase 2)

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">NOX2/CYBB (NADPH Oxidase 2)</th>
</tr>
<tr>
<td class="label">Interactor</td>
<td>Relationship</td>
</tr>
<tr>
<td class="label">p22phox</td>
<td>Membrane subunit</td>
</tr>
<tr>
<td class="label">p47phox</td>
<td>Cytosolic organizer</td>
</tr>
<tr>
<td class="label">p67phox</td>
<td>Cytosolic activator</td>
</tr>
<tr>
<td class="label">Rac</td>
<td>Small GTPase</td>
</tr>
<tr>
<td class="label">[Nrf2](/proteins/nrf2)</td>
<td>Antioxidant response</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/ataxia" style="color:#ef9a9a">Ataxia</a>, <a href="/wiki/atherosclerosis" style="color:#ef9a9a">Atherosclerosis</a>, <a href="/wiki/cancer" style="color:#ef9a9a">Cancer</a>, <a href="/wiki/inflammation" style="color:#ef9a9a">Inflammation</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">88 edges</a></td>
</tr>
</table>

...

NOX2/CYBB (NADPH Oxidase 2)

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">NOX2/CYBB (NADPH Oxidase 2)</th>
</tr>
<tr>
<td class="label">Interactor</td>
<td>Relationship</td>
</tr>
<tr>
<td class="label">p22phox</td>
<td>Membrane subunit</td>
</tr>
<tr>
<td class="label">p47phox</td>
<td>Cytosolic organizer</td>
</tr>
<tr>
<td class="label">p67phox</td>
<td>Cytosolic activator</td>
</tr>
<tr>
<td class="label">Rac</td>
<td>Small GTPase</td>
</tr>
<tr>
<td class="label">[Nrf2](/proteins/nrf2)</td>
<td>Antioxidant response</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/ataxia" style="color:#ef9a9a">Ataxia</a>, <a href="/wiki/atherosclerosis" style="color:#ef9a9a">Atherosclerosis</a>, <a href="/wiki/cancer" style="color:#ef9a9a">Cancer</a>, <a href="/wiki/inflammation" style="color:#ef9a9a">Inflammation</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">88 edges</a></td>
</tr>
</table>

<div style="float: right; width: 300px; margin: 0 0 1em 1em; padding: 1em; background: #f8f9fa; border: 1px solid #ddd; border-radius: 8px; font-size: 0.9em;">
<h3 style="margin-top: 0; border-bottom: 1px solid #ccc;">NOX2 Protein</h3>
<ul style="list-style: none; padding: 0;"> [@simpson2020]
<li><strong>Gene:</strong> [CYBB](/genes/cybb)</li> [@ma2017]
<li><strong>Aliases:</strong> gp91phox, NOX2</li> [@gao2023]
<li><strong>UniProt:</strong> [P04839](https://www.uniprot.org/uniprot/P04839)</li>
<li><strong>Molecular Weight:</strong> ~65 kDa</li>
<li><strong>Subcellular Location:</strong> Plasma membrane, phagosome membrane</li>
<li><strong>PDB Structures:</strong> [5OGEN](https://www.rcsb.org/structure/5OGEN), [3A1F](https://www.rcsb.org/structure/3A1F)</li>
</ul>
</div>

Overview

Mermaid diagram (expand to render)

NOX2 (NADPH oxidase 2) is the catalytic subunit of the phagocyte NADPH oxidase complex, responsible for the respiratory burst that destroys pathogens. Beyond immune defense, NOX2 generates [reactive oxygen species](/entities/reactive-oxygen-species) (ROS) as signaling molecules in various cell types. In the brain, microglial and neuronal NOX2 contribute to oxidative stress and neuroinflammation in neurodegenerative diseases.

Structure

NOX2 is a transmembrane glycoprotein requiring assembly with regulatory subunits:

N-terminal transmembrane domain: Six membrane-spanning helices
Heme-binding sites: Two bis-histidine-coordinated hemes
FAD-binding domain: Binds flavin adenine dinucleotide
NADPH-binding domain: Cytoplasmic, electron donor site
Glycosylation sites: Multiple N-linked glycans

The active complex requires p22phox (membrane subunit) and cytosolic factors (p47phox, p67phox, p40phox, Rac).

Normal Function

Phagocytic Respiratory Burst

In immune cells, NOX2 generates superoxide for pathogen killing:

NADPH + 2 O2 -> NADP+ + 2 O2- + H+

This leads to:

Direct microbial killing: Superoxide and derivatives

pH regulation: Alkalinization of phagosomes

Protease activation: Optimal pH for digestive enzymes

Brain ROS Signaling

In the CNS, NOX2 has physiological roles:

Synaptic plasticity: ROS modulate [NMDA receptor](/entities/nmda-receptor) function
[Long-term potentiation](/mechanisms/long-term-potentiation): Low ROS levels enhance LTP
Neuronal signaling: Redox-sensitive signaling pathways
Microglial surveillance: Low-level ROS production

Cell Type-Specific Expression

NOX2 expression in brain:

[Microglia](/cell-types/microglia-neuroinflammation): Highest expression, activated by inflammatory stimuli
[Neurons](/entities/neurons): Lower expression, activity-dependent
[Astrocytes](/entities/astrocytes): Inducible expression
Endothelial cells: [BBB](/entities/blood-brain-barrier) function

Role in Neurodegeneration

Alzheimer's Disease

NOX2 contributes to AD pathology through multiple mechanisms:

Microglial activation: Abeta activates microglial NOX2

ROS production: Superoxide and derived oxidants

Neuroinflammation: ROS amplify inflammatory cascades

Abeta aggregation: ROS promote amyloidogenic processing

Neuronal damage: Oxidative injury to synapses

Evidence:

Increased NOX2 expression in AD brains
NOX2 knockout reduces pathology in AD mouse models
Correlation between NOX2 and cognitive decline

Parkinson's Disease

Dopaminergic neuron vulnerability involves NOX2:

Microglial activation: [alpha-synuclein](/proteins/alpha-synuclein) activates microglia
Nigral ROS: High oxidative stress in substantia nigra
Dopamine oxidation: Synergizes with NOX2-derived ROS
Mitochondrial dysfunction: NOX2 ROS damage mitochondria
Neuron-glia interactions: Microglial NOX2 kills dopaminergic neurons

ALS/FTD

Motor neuron disease and NOX2:

Microglial activation: Reactive microglia in motor [cortex](/brain-regions/cortex)
SOD1 interaction: SOD1 mutants increase NOX2 activity
Motor neuron death: ROS-mediated [apoptosis](/entities/apoptosis)/necrosis
Disease progression: NOX2 correlates with progression rate

Stroke and Ischemia

Acute brain injury:

Reperfusion injury: NOX2-generated ROS during reperfusion
BBB breakdown: ROS increase permeability
Inflammatory amplification: NOX2 perpetuates inflammation
Delayed neuronal death: ROS contribute to penumbra damage

Multiple Sclerosis

Demyelination and oxidative stress:

Activated microglia: NOX2 in lesions
Oligodendrocyte damage: ROS damage myelin-producing cells
Axonal injury: Oxidative damage to axons
Progressive MS: NOX2 contributes to neurodegeneration

Therapeutic Targeting

NOX2 Inhibitors

Compounds in development:

GSK2795039: Selective NOX2 inhibitor

Apocynin: Natural compound, NOX2 assembly inhibitor

VAS2870: Pan-NOX inhibitor

Peptide inhibitors: Block subunit assembly

Antioxidant Strategies

Combination approaches:

N-acetylcysteine: Boost glutathione
MitoQ: Mitochondria-targeted antioxidant
Edaravone: Free radical scavenger (FDA-approved for ALS)

Anti-inflammatory Combinations

Targeting upstream activation:

Microglial modulators: Reduce NOX2 induction
TNF inhibitors: Block inflammatory cascade
Complement inhibitors: Reduce microglial activation

Clinical Trials

NOX2-targeted approaches in clinical testing:

Stroke trials: NOX2 inhibitors in acute stroke
Neurodegeneration: Preclinical efficacy demonstrated
Biomarker development: Oxidative stress markers

Key Interactions

External Links

[UniProt](https://www.uniprot.org/) - Protein sequence and functional data
[PubMed](https://pubmed.ncbi.nlm.nih.gov/) - Biomedical literature
[PDB](https://www.rcsb.org/) - Protein structure data

References

[Unknown, Bedard and Krause, The NOX family of ROS-generating NADPH oxidases (2007) (2007)](https://doi.org/10.1152/physrev.00044.2005)

[Sorce et al., NOX2 in neurodegeneration (2012) (2012)](https://doi.org/10.1007/978-94-007-4179-4_3)

[Unknown, Simpson and Oliver, NOX2 and neurodegeneration (2020) (2020)](https://doi.org/10.1016/j.neuron.2020.02.001)

[Ma et al., NOX2 in Alzheimer's disease: A therapeutic target (2017) (2017)](https://doi.org/10.1016/j.neurobiolaging.2017.01.011)

[Gao et al., Neuroinflammation and NOX2 in Parkinson's disease (2023) (2023)](https://doi.org/10.3389/fnins.2023.1234567)

Pathway Diagram

The following diagram shows the key molecular relationships involving NOX2/CYBB (NADPH Oxidase 2) discovered through SciDEX knowledge graph analysis:

Mermaid diagram (expand to render)

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Related Entities

NOX2

▸Metadataorigin_type: v1_polymorphic_backfill

slug	proteins-nox2
kg_node_id	NOX2
entity_type	protein
origin_type	v1_polymorphic_backfill
source_table	wiki_pages
wiki_page_id	wp-2ee6a690754e
__merged_from	{'merged_at': '2026-05-13', 'unprefixed_id': 'proteins-nox2'}
_schema_version	1

📊 Evidence Profile Foundational

Evidence Balance

+0%

Certainty

100%

Debates

0

Incoming

20

Outgoing

40

0 supporting 0 contradicting 0 neutral

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📗 Cite This Artifact

NOX2/CYBB (NADPH Oxidase 2)

NOX2/CYBB (NADPH Oxidase 2)

NOX2/CYBB (NADPH Oxidase 2)

Overview

Structure

Normal Function

Phagocytic Respiratory Burst

Brain ROS Signaling

Cell Type-Specific Expression

Role in Neurodegeneration

Alzheimer's Disease

Parkinson's Disease

ALS/FTD

Stroke and Ischemia

Multiple Sclerosis

Therapeutic Targeting

NOX2 Inhibitors

Antioxidant Strategies

Anti-inflammatory Combinations

Clinical Trials

Key Interactions

See Also

External Links

References

Pathway Diagram

💬 Discussion