| NOXO1 Protein |
|---|
| Symbol | NOXO1 |
| Full Name | NADPH Oxidase Organizer 1 |
| Gene | [NOXO1](/genes/noxo1) |
| UniProt ID | [Q8NFA2](https://www.uniprot.org/uniprotkb/Q8NFA2) |
| Molecular Weight | 41.1 kDa |
| Length | 366 amino acids |
| Subcellular Location | Cytoplasm, plasma membrane (with NOX1 complex) |
| Associated Diseases | Inflammatory bowel disease, Cancer, Neuroinflammation |
--- is a protein encoded by the NOXO1 gene that ### NOX1 Complex Organization. This page describes its structure, normal nervous system function, role in neurodegenerative disease, and potential as a therapeutic target.
NOXO1 (p41nox) is the organizer subunit for the NOX1 NADPH oxidase complex:
¶ Domain Architecture
- PX domain (residues 1-140): Phox homology domain, binds phosphoinositides
- SH3 domains (two): Src homology 3 domains for protein-protein interactions
- Proline-rich regions: Mediate binding to NOXA1
- PB1 domain: Similar to p47phox but constitutively active
NOXO1 is the homolog of p47phox but with key differences:
- Lacks the autoinhibitory region present in p47phox
- Constitutively membrane-associated
- Does not require phosphorylation for activation
NOXO1 is essential for NOX1 NADPH oxidase assembly:
- Membrane recruitment: PX domain binds plasma membrane phosphoinositides
- NOX1 interaction: Bridges cytosolic components to membrane-bound NOX1
- NOXA1 binding: SH3 domains interact with NOXA1 proline-rich regions
- Complex stabilization: Maintains assembled NOX1 complex at membrane
- Organizes NOX1 complex for superoxide (O2•−) production
- Important for epithelial cell antimicrobial defense
- Contributes to cellular signaling via redox mechanisms
- High expression in colon epithelium
- Present in vascular smooth muscle
- Lower levels in brain and other tissues
NOXO1 contributes to neurodegenerative processes through ROS:
- Microglial activation: NOX1/NOXO1 complex in activated microglia
- ROS-mediated damage: Superoxide production damages neurons
- BBB dysfunction: ROS from NOX1 contributes to barrier breakdown
- Inflammatory amplification: ROS activates NF-κB signaling
- Aβ-induced activation: Aβ peptides may activate NOX1 complex
- Oxidative stress: NOXO1/NOX1 contributes to AD oxidative damage
- Tau phosphorylation: ROS from NOX1 affects kinase/phosphatase balance
- Dopaminergic vulnerability: ROS from NOX1 may damage dopaminergic neurons
- α-synuclein effects: Aggregated α-synuclein may activate NOX complexes
- Neuroinflammation: Contributes to microglial ROS production
- Vascular ROS: NOX1/NOXO1 in cerebral vessels
- Endothelial dysfunction: Contributes to vascular dysfunction
- Blood-brain barrier: ROS disrupts tight junctions
| Component |
Role |
Interaction |
| NOX1 |
Catalytic subunit |
Membrane-bound flavocytochrome |
| NOXO1 |
Organizer |
Bridges NOXA1 to NOX1 |
| NOXA1 |
Activator |
Provides FAD binding site |
| p22phox |
Stabilizer |
Membrane anchor for NOX1 |
¶ PX Domain Function
- Binds PI(3)P, PI(3,4)P2, and PI(4,5)P2
- Constitutive membrane localization
- Different lipid specificity than p47phox
Unlike p47phox, NOXO1 does not require:
- Protein kinase C phosphorylation
- WASP/SCAR proteins for activation
- Conformational change for membrane binding
- ML171: NOX1-selective inhibitor (also affects NOX2)
- Compound development: Ongoing efforts for NOX1-specific inhibitors
- Apocynin: Pan-NOX inhibitor (natural compound)
- VAS2870: NOX2/4 inhibitor with some NOX1 activity
- GKT137831 (Setanaxib): NOX1/4 dual inhibitor in clinical trials
- Targeting NOXO1-NOXA1 interaction
- Disrupting PX domain membrane binding
- Reducing NOX1-mediated neuroinflammation
| Interacting Protein |
Function |
Disease Relevance |
| NOX1 |
Catalytic partner |
ROS generation |
| NOXA1 |
Activator subunit |
Complex assembly |
| p22phox |
Membrane anchor |
Complex stability |
| PI(3)P |
Membrane lipid |
Membrane targeting |