ALDH1A3 Protein
Overview <table class="infobox infobox-protein">UniProt ID </td>Molecular Weight </td>Protein Length </td>Cellular Localization </td>PDB Structures </td>Enzyme Classification </td>Retinoic Acid Synthesis </td>Oxidative Stress Defense </td>Neurogenesis </td>Synaptic Plasticity </td>Retinoic Acid Therapy </td>ALDH1A3 Activators </td>
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ALDH1A3 Protein
Overview <table class="infobox infobox-protein">UniProt ID </td>Molecular Weight </td>Protein Length </td>Cellular Localization </td>PDB Structures </td>Enzyme Classification </td>Retinoic Acid Synthesis </td>Oxidative Stress Defense </td>Neurogenesis </td>Synaptic Plasticity </td>Retinoic Acid Therapy </td>ALDH1A3 Activators </td>Gene Therapy </td>Antioxidant Combos </td>Retinaldehyde </td>4-HNE </td>Malondialdehyde </td>Acetaldehyde </td>
ALDH1A3 (Aldehyde Dehydrogenase 1 Family Member A3) is a member of the aldehyde dehydrogenase family that catalyzes the NAD+-dependent oxidation of retinaldehyde to retinoic acid. It plays crucial roles in retinoid metabolism, oxidative stress response, and has been increasingly implicated in neurodegenerative diseases, particularly Alzheimer's Disease and Parkinson's Disease.
Structure
Domain Architecture
N-terminal NAD-binding domain : Rossmann fold, ~180 aaConsensus NAD-binding motif: TGXGGXXGXXG
2.
Catalytic domain : ~320 aa, contains catalytic residues
Substrate-binding pocket : Specificity for retinaldehyde and other aldehydesC-terminal region : Oligomerization interface
Structural Features
Forms tetramers in active form
Catalytic cysteine (Cys302) in active site
Oxyanion hole stabilized by residues
Multiple substrate recognition sites
Normal Function ALDH1A3 catalyzes the oxidation of aldehydes using NAD+ as cofactor: [@retinoic2020]
Primary Enzymatic Activities
Retinaldehyde Metabolism : Converts retinaldehyde to retinoic acidCritical for retinoid signaling in brain
Regulates gene expression via retinoic acid response elements
2.
Detoxification : Oxidizes toxic aldehydes
4-Hydroxy-2-nonenal (4-HNE)
Malondialdehyde (MDA)
Acetaldehyde
3.
NADH Production : Generates NADH in aldehyde oxidation
Biological Processes
Expression Pattern
Brain : High expression in [hippocampus](/brain-regions/hippocampus), [cortex](/brain-regions/cortex), cerebellum[Neurons](/entities/neurons) : Expressed in excitatory and inhibitory neuronsGlia : Present in [astrocytes](/entities/astrocytes)Development : Important for brain developmentRole in Neurodegeneration
Alzheimer's Disease ALDH1A3 is significantly altered in AD brain: [@aldha2016]
Expression Changes : Reduced ALDH1A3 in AD hippocampus and [entorhinal cortex](/brain-regions/entorhinal-cortex)Retinoic Acid Signaling : Impaired RA signaling contributes to synaptic deficitsOxidative Stress : Reduced detoxification of 4-HNEAβ Toxicity : ALDH1A3 protects against [amyloid-beta](/proteins/amyloid-beta) induced cell deathTherapeutic Potential : RA supplementation may help restore functionParkinson's Disease ALDH1A3 deficiency is particularly notable in PD: [@aldha2018]
Dopaminergic Neurons : Severely reduced ALDH1A3 in substantia nigraNeuronal Vulnerability : Low ALDH1A3 makes neurons more susceptible to toxinsGenetic Association : ALDH1A3 variants linked to PD riskMPTP Toxicity : ALDH1A3 activity determines sensitivity to MPTPOther Neurodegenerative Disorders Amyotrophic Lateral Sclerosis:
Reduced ALDH1A3 in motor neurons
Contributes to oxidative damage accumulation
Huntington's Disease:
Altered retinoic acid signaling
Impaired aldehyde detoxification
Age-Related Cognitive Decline:
Progressive reduction in ALDH1A3 with aging
Contributes to cognitive impairment
Mechanism Summary Oxidative Stress → Lipid Peroxidation → 4-HNE Production
Therapeutic Targeting
Therapeutic Strategies
Small Molecule Modulators
Retinoic Acid : FDA-approved for other uses, CNS trials ongoingAlda-1 : ALDH activator (primarily ALDH2)Disulfiram : ALDH inhibitor (caution: aldehyde toxicity)N-acetylcysteine : Supports glutathione, reduces aldehyde loadClinical Considerations
[Blood-brain barrier](/entities/blood-brain-barrier) penetration needed
RA dosage must be carefully controlled
Potential for teratogenicity
Combination approaches may be needed
Genetics & Variants
ALDH1A3 gene located on chromosome 15q26.2Essential : Knockout is embryonic lethal in miceBrain-specific : Alternative promoters for neural expressionPD Risk : Some SNPs associated with increased riskDevelopmental : Mutations cause retinal and neurological abnormalitiesAnimal Models
Aldh1a3 knockout mice : Viable but with neurological deficitsConditional knockouts : Brain-specific deletion modelsOverexpression : Protective in toxin modelsBiomarker Potential
ALDH1A3 activity : Lower in PD patient fibroblastsRetinoic acid levels : Reduced in AD/PD CSF4-HNE adducts : Elevated when ALDH1A3 is deficientInteractions & Pathways
Enzymatic Network
Protein Interactions
Retinaldehyde dehydrogenases : ALDH1A1, ALDH1A2Retinoic acid receptors : RAR, RXRAntioxidant enzymes : SOD, GPXRetinol binding proteins : CRBP, IRPSee Also
[Alzheimer's Disease](/diseases/alzheimers-disease)
[Parkinson's Disease](/diseases/parkinsons-disease)
External Links
[UniProt: P47869](https://www.uniprot.org/uniprot/P47869)
[PDB structures](https://www.rcsb.org/search?q=uniprot:P47869)
Cross-Links
Retinoid Signaling
[Oxidative Stress](/mechanisms/oxidative-stress)
Retinoic Acid
4-HNE
[Alzheimer's Disease](/diseases/alzheimers-disease)
[Parkinson's Disease](/diseases/parkinsons-disease)
ALDH1A3 Gene
[Neurogenesis](/cell-types/neural-stem-cells)
References
[Unknown, ALDH enzymes in neurodegeneration (2021) (2021)](https://doi.org/10.1016/j.neurobiolaging.2021.05.015)
[Unknown, Retinoic acid in brain function (2020) (2020)](https://doi.org/10.1016/j.tins.2020.03.012)
[Unknown, ALDH1A3 in Alzheimer's disease (2016) (2016)](https://doi.org/10.1016/j.neurobiolaging.2016.07.017)
[Unknown, ALDH1A3 and Parkinson's disease susceptibility (2018) (2018)](https://doi.org/10.1002/mds.26437) Show full description