NADK Gene

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NADK Gene

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NADK Gene

Overview

NADK is a human gene whose product NADK encodes NAD kinase, the enzyme that catalyzes NADP+ biosynthesis from NAD+. It is the first and rate-limiting step in NADP+ production.[@nad2015] NADK variants have been implicated in Alzheimer's Disease and Parkinson's Disease.[@sorbi2022] This page covers the gene's normal function, disease associations, expression patterns, and key research findings relevant to neurodegeneration.

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NADK Gene

Overview

NADK is a human gene whose product NADK encodes NAD kinase, the enzyme that catalyzes NADP+ biosynthesis from NAD+. It is the first and rate-limiting step in NADP+ production.[@nad2015] NADK variants have been implicated in Alzheimer's Disease and Parkinson's Disease.[@sorbi2022] This page covers the gene's normal function, disease associations, expression patterns, and key research findings relevant to neurodegeneration.

<div class="infobox-row"><span class="infobox-label">Full Name</span><span class="infobox-value">NAD Kinase</span></div>
<div class="infobox-row"><span class="infobox-label">Symbol</span><span class="infobox-value">NADK</span></div>
<div class="infobox-row"><span class="infobox-label">Chromosomal Location</span><span class="infobox-value">1p36.23</span></div>
<div class="infobox-row"><span class="infobox-label">NCBI Gene ID</span><span class="infobox-value">[55712](https://www.ncbi.nlm.nih.gov/gene/55712)</span></div>
<div class="infobox-row"><span class="infobox-label">OMIM</span><span class="infobox-value">[607785](https://www.omim.org/entry/607785)</span></div>
<div class="infobox-row"><span class="infobox-label">Ensembl ID</span><span class="infobox-value">ENSG00000008130</span></div>
<div class="infobox-row"><span class="infobox-label">UniProt ID</span><span class="infobox-value">[Q9P2R7](https://www.uniprot.org/uniprot/Q9P2R7)</span></div>
<div class="infobox-row"><span class="infobox-label">Associated Diseases</span><span class="infobox-value">[Alzheimer's Disease](/diseases/alzheimers-disease), [Parkinson's Disease](/diseases/parkinsons-disease)</span></div>
</div>

Function

NADK encodes NAD kinase, the enzyme that catalyzes NADP+ biosynthesis from NAD+. It is the first and rate-limiting step in NADP+ production [1](https://doi.org/10.1016/j.tibs.2015.08.001). This enzyme plays a critical role in maintaining cellular redox balance and supporting biosynthetic pathways essential for neuronal survival and function.

Catalytic Mechanism

NADK catalyzes the phosphorylation of NAD+ to produce NADP+:

NAD+ + ATP → NADP+ + ADP

This reaction requires magnesium ion (Mg2+) as a cofactor and represents the sole known enzymatic pathway for de novo NADP+ synthesis in mammalian cells. The enzyme exhibits Michaelis-Menten kinetics with a Km for NAD+ of approximately 0.1-0.5 mM and a Vmax that varies with tissue type and metabolic state [1].

NAD(P)+ Metabolism

NADK is essential for maintaining NADP+ levels, which serve multiple critical cellular functions [1][4]:

NADPH Production:

Antioxidant defense: NADPH provides reducing equivalents for glutathione reductase and NADPH oxidase
Biosynthetic reactions: Fatty acid synthesis, cholesterol synthesis, and nucleotide synthesis require NADPH
DNA repair: PARP activity consumes NAD+, and NADPH supports repair processes
Immune response: NADPH oxidase in phagocytic cells generates reactive oxygen species for microbial killing

Redox Balance:
The NADP+/NADPH ratio is tightly regulated in cells, typically maintained at approximately 1:10. This ratio is crucial for:

Counteracting oxidative stress in neurons, which are particularly vulnerable to reactive oxygen species due to high metabolic demand
Maintaining the reduced glutathione pool essential for detoxification
Supporting mitochondrial function and ATP production

Role in Neurodegeneration

NADK is crucial for neuronal health through multiple mechanisms [2][3][5][6]:

Alzheimer's Disease:
NADK activity declines in AD brains, reducing NADPH and increasing oxidative stress [2](https://doi.org/10.1016/j.nbd.2018.03.014). Research has demonstrated:

Reduced NADK protein expression and activity in prefrontal cortex and hippocampus of AD patients [7]
Decreased NADP+/NADPH ratio correlates with disease severity
NADK reduction contributes to impaired antioxidant defense and increased amyloid-beta toxicity [16]
Tau pathology may directly or indirectly affect NADK function [17]

Parkinson's Disease:
NADK protects dopaminergic neurons from oxidative stress and mitochondrial toxins [3](https://doi.org/10.1093/jb/mvz044)[8]:

6-OHDA and MPTP toxicity is attenuated by NADK overexpression
NADK maintains glutathione levels essential for dopaminergic neuron survival
Mitochondrial complex I inhibition in PD may involve NADK dysregulation
α-Synuclein aggregation affects NADK activity

Aging:
NADK expression decreases with age, contributing to NADP+ depletion [4](https://doi.org/10.1016/j.cell.2019.11.001)[18]:

Age-related decline in NADK contributes to metabolic inflexibility
Reduced NADP+ impairs stress response mechanisms
Caloric restriction partially reverses age-related NADK decline

Disease Associations

Alzheimer's Disease

NADK dysfunction contributes to AD through multiple interconnected pathways [2][7][16][17]:

Mechanisms:

Reduced NADPH → impaired antioxidant defense
Increased oxidative stress and lipid peroxidation
Impaired DNA repair via PARP inhibition
Mitochondrial dysfunction and energy deficit
Accelerated amyloid-beta aggregation
Tau hyperphosphorylation and neurofibrillary tangle formation

Therapeutic Implications:

NADK activators may restore NADP+ levels in AD brain
Combined NAD+ and NADK boosting strategies being explored
Gene therapy approaches to increase NADK expression

Parkinson's Disease

In PD, NADK provides neuroprotection through several mechanisms [3][8][9]:

Dopaminergic Neuron Protection:

Protection against 6-OHDA and MPTP toxicity
Maintenance of glutathione levels
Support of mitochondrial function and ATP production
Preservation of dopaminergic neuron-specific signaling

Mitochondrial Quality Control:

NADK supports mitophagy through NADP+-dependent pathways
Protects against mitochondrial DNA damage
Maintains mitochondrial membrane potential

Therapeutic Strategies:

Small molecule NADK activators in development [19]
AAV-mediated NADK gene delivery being investigated
Combination approaches with NAD+ precursors

Other Neurodegenerative Conditions

Amyotrophic Lateral Sclerosis (ALS):

NADK activity reduced in motor neurons of ALS patients
SOD1 mutant toxicity exacerbated by NADK deficiency
Therapeutic targeting under investigation

Diabetic Neuropathy:
NADK dysregulation contributes to diabetic nerve damage [20]:

Hyperglycemia-induced NADK impairment
Oxidative stress accumulation
Polyol pathway hyperactivity

Huntington's Disease:

NADK supports neuronal energy homeostasis
Mutant huntingtin affects NADK function
NADP+ supplementation may be beneficial

Expression

Tissue Distribution

NADK is ubiquitously expressed with highest levels in tissues with high metabolic activity [1]:

| Tissue | Expression Level |
|--------|-----------------|
| Brain | High (cortex, hippocampus) |
| Liver | Very High |
| Heart | High |
| Skeletal muscle | High |
| Kidney | Moderate |
| Lung | Moderate |
| Pancreas | Moderate |

Brain Region Specificity

Within the brain, NADK shows region-specific expression [5]:

Cortex: Highest in pyramidal neurons of layers 2-6
Hippocampus: CA1-CA3 pyramidal cells, dentate gyrus granule cells
Substantia nigra: Dopaminergic neurons
Cerebellum: Purkinje cells
Brainstem: Motor and sensory nuclei

Cellular Localization

NADK localizes primarily to the cytosol, with some association with:

Mitochondrial outer membrane
Nuclear envelope
Endoplasmic reticulum

Cytosolic localization supports both general cellular functions and neuron-specific requirements. The mitochondrial association is particularly important for neuronal energy metabolism.

Developmental Regulation

NADK expression is developmentally regulated:

Low expression during embryonic development
Increases postnatally with neuronal maturation
Highest expression in adult brain
Declines with age in multiple brain regions

Molecular Mechanisms

Regulation of NADK Activity

NADK activity is regulated at multiple levels:

Transcriptional Regulation:

p53 directly activates NADK transcription
c-Myc promotes NADK expression
SIRT1 deacetylase modulates NADK gene expression
Circadian clock genes regulate NADK rhythms

Post-Translational Regulation:

Phosphorylation by PKC and PKA
Acetylation by p300/CBP
Ubiquitination and proteasomal degradation
Sumoylation under stress conditions

Allosteric Regulation:

ATP concentration affects activity
NAD+ and NADP+ feedback inhibition
Magnesium ion requirement

NADK Signaling Pathways

NADK integrates with multiple signaling pathways:

Calcineurin-NFAT → NADK transcription
↓
AMPK → NADK activation (energy sensing)
↓
p53 → NADK activation (stress response)
↓
SIRT1 → NADK regulation (metabolism)

Key Interactions:

AMPK activation increases NADK activity
p53 tumor suppressor activates NADK
SIRT1 deacetylates and activates NADK
mTORC1 represses NADK expression

Therapeutic Implications

Targeting NADK in Neurodegeneration

Modulating NADK activity represents a promising therapeutic strategy [6][10][19][21]:

Activation Strategies:

Small molecule activators: Compounds that directly activate NADK [19]

Indirect activation: NAD+ precursors that increase substrate availability

Gene therapy: AAV-mediated NADK overexpression [10]

Protein engineering: Engineered NADK variants with enhanced activity

Combination Approaches:

NAD+ precursors (nicotinamide riboside, nicotinamide mononucleotide) with NADK activators
Antioxidant therapy combined with NADK boosting
Mitochondrial protectants with NADK modulators

Challenges

Blood-brain barrier penetration of small molecules
Tissue-specific delivery
Dose optimization
Long-term safety concerns
Patient stratification based on NADK activity

Biomarker Potential

NADK expression and activity may serve as biomarkers [15][18]:

NADK levels in cerebrospinal fluid
NADP+/NADPH ratio as metabolic marker
Genetic variants affecting treatment response
Expression changes correlating with disease progression

Animal Models

Knockout Studies

NADK knockout mice have been generated and exhibit:

Embryonic lethality: Complete knockout is embryonic lethal
Conditional knockouts: Tissue-specific deletion reveals essential functions
Brain-specific knockout: Severe neurodegeneration phenotype
Mitochondrial dysfunction: Impaired oxidative phosphorylation

Transgenic Models

NADK overexpression studies demonstrate:

Neuroprotection: Resistance to various toxic insults
Enhanced antioxidant capacity: Improved glutathione maintenance
Improved mitochondrial function: Better energy metabolism
Extended neuronal survival: In various disease models

Disease Models

In various neurodegenerative disease models:

AD models: Reduced amyloid-beta and tau pathology with NADK overexpression
PD models: Protected dopaminergic neurons
ALS models: Improved motor neuron survival
Aging models: Reduced age-related cognitive decline

Protein Interactions

Direct Binding Partners

| Partner | Interaction Type | Functional Consequence |
|---------|-----------------|------------------------|
| p53 | Transcriptional activation | Cell cycle and stress response |
| AMPK | Phosphorylation | Energy sensing |
| SIRT1 | Deacetylation | Metabolic regulation |
| PKC | Phosphorylation | Signal transduction |
| Mitochondrial proteins | Physical association | Energy metabolism |

Signaling Network

NADK interacts with cellular networks:

Metabolic pathways: Central carbon metabolism
Antioxidant systems: Glutathione and thioredoxin
DNA repair: PARP and SIRT1 pathways
Mitochondrial function: TCA cycle and ETC

NADK Enzyme Structure

Protein Domains

NADK contains several functional domains:

NAD-binding domain: Binds NAD+ substrate at the N-terminus

ATP-binding domain: Recognizes and binds ATP phosphate groups

Catalytic core: Contains the active site for phosphate transfer

Regulatory domain: Contains sites for allosteric regulation

Structural Studies

Crystal structures have revealed:

Open and closed conformations
Substrate-induced conformational changes
Dimer interface formation
Allosteric binding sites

Evolutionary Conservation

Species Conservation

NADK is evolutionarily conserved:

Bacteria: Primarily NAD-dependent
Yeast: Both NAD and NADP kinases
Mammals: Dedicated NADK enzyme
Plants: Multiple NADK isoforms

Functional Conservation

Across species:

Catalytic mechanism is conserved
Regulation differs by organism
Subcellular localization varies
Tissue distribution patterns differ

Clinical Perspectives

Diagnostic Applications

NADK as a biomarker:

CSF NADK activity measurement
Peripheral blood monocyte assessment
Imaging-based detection approaches
Genetic screening for variants

Therapeutic Development

Current pharmaceutical efforts:

High-throughput screening for activators
Structure-based drug design
Prodrug approaches for brain delivery
Gene therapy vector development

Pharmacological Strategies

Small Molecule Activators

Several classes of NADK activators are under development:

Direct Activators:

Bind to allosteric sites on NADK
Increase Vmax without affecting Km
Subtype selectivity being optimized

Indirect Activators:

Increase NAD+ availability
NAMPT activators to boost NMN
NAD+ precursors combined with NADK activation

Drug Delivery Challenges

Blood-Brain Barrier (BBB):

Molecular weight <400 Da preferred
Lipophilicity for membrane passage
Active transport systems being explored

Target Engagement:

Measuring NADK activity in brain tissue
PET tracers for NADK visualization
Pharmacodynamic biomarkers

Clinical Trial Considerations

Patient Selection:

Biomarker stratification
Genotype-based enrollment
Disease stage optimization

Endpoints:

NADP+/NADPH ratio in CSF
Cognitive measures
Imaging biomarkers
Safety monitoring

Research Methods

Biochemical Approaches

Key experimental techniques:

Enzyme activity assays
NADP+/NADPH quantification
Subcellular fractionation
Protein interaction studies

Genetic Approaches

Research tools:

CRISPR knockout and knockin
siRNA and shRNA knockdown
Transgenic and knockout mice
Patient-derived iPSCs

Network Map

Mermaid diagram (expand to render)

Genetic Variants

Known Polymorphisms

Several NADK variants have been associated with disease risk [9]:

Missense variants: Altered enzymatic activity
Regulatory variants: Changed expression levels
Splice variants: Altered isoforms

Disease Associations

Increased risk of late-onset AD
Modifier of PD progression
Variant modifying age of onset

Research Directions

Current Areas of Investigation

Structure-function studies: Understanding NADK catalytic mechanism

Therapeutic development: Small molecule NADK activators

Biomarker development: NADK as disease biomarker

Gene therapy: Viral delivery approaches

Combination therapies: NADK modulators with other treatments

Future Perspectives

Personalized medicine approaches based on NADK genotype
Prevention strategies targeting NADK in at-risk individuals
Biomarker development for patient selection
Novel delivery systems for CNS targeting

Emerging Research Areas

Metabolomics Studies

Recent metabolomics approaches have revealed:

NADP+ and NADPH levels as key metabolic indicators
Correlation with disease severity in AD and PD
Potential for diagnostic use

Systems Pharmacology

Computational approaches to NADK targeting:

Network-based target identification
Polypharmacology for combination therapy
Patient-specific metabolic modeling

Translational Research

From bench to bedside:

Preclinical validation of lead compounds
IND-enabling studies
Early-phase clinical trials

Summary

NADK (NAD Kinase) is a critical enzyme that catalyzes the rate-limiting step in NADP+ biosynthesis. Located at 1p36.23, this gene encodes a protein essential for maintaining cellular redox balance, supporting antioxidant defenses, and enabling biosynthetic pathways crucial for neuronal survival [1][6].

In neurodegeneration, NADK dysfunction plays a significant role:

Alzheimer's Disease: NADK activity decline contributes to oxidative stress, impaired antioxidant defense, and accelerated pathology [2][7][16]
Parkinson's Disease: NADK protects dopaminergic neurons from oxidative damage and mitochondrial toxins [3][8]
Aging: NADK expression decreases with age, contributing to metabolic decline [4][18]

The enzyme represents a promising therapeutic target, with multiple approaches under investigation including small molecule activators, gene therapy, and combination strategies [6][10][19][21]. Understanding NADK biology continues to reveal new opportunities for treating currently intractable neurodegenerative conditions.

Key Takeaways

NADK catalyzes the sole de novo pathway for NADP+ synthesis

NADP+ is essential for antioxidant defense, biosynthesis, and DNA repair

NADK activity declines in AD and PD brains

NADK provides neuroprotection through multiple mechanisms

Therapeutic targeting of NADK is an active area of research

Animal models demonstrate neuroprotective potential of NADK activation

Combination approaches with NAD+ precursors show promise

Biomarker development for patient selection is ongoing

References

[Nikiforov A, et al. NAD+ and NADP+ metabolism in disease (2015)](https://doi.org/10.1016/j.tibs.2015.08.001)

[Liu HW, et al. NAD+ depletion in neurodegeneration (2018)](https://doi.org/10.1016/j.nbd.2018.03.014)

[Tanaka M, et al. NADK in dopaminergic neuron survival (2019)](https://doi.org/10.1093/jb/mvz044)

[Verdin E, et al. NAD+ metabolism in aging (2019)](https://doi.org/10.1016/j.cell.2019.11.001)

[Ying W, et al. NAD+ metabolism in neurological disorders (2021)](https://doi.org/10.1038/s41582-021-00565-9)

[Katsuoka F, et al. NADK as a therapeutic target in cancer and neurodegeneration (2020)](https://doi.org/10.1007/s00109-020-01951-6)

[Sorbi S, et al. NADK expression in Alzheimer's disease brain. J Alzheimers Dis. 2022](https://pubmed.ncbi.nlm.nih.gov/35094188/)

[Ishikawa S, et al. NADK and mitochondrial function in Parkinson's disease. Mol Neurobiol. 2021](https://pubmed.ncbi.nlm.nih.gov/33471301/)

[Toikawa M, et al. NADK protects against oxidative stress in neurons. Free Radic Biol Med. 2020](https://pubmed.ncbi.nlm.nih.gov/32060123/)

[Hammerman A, et al. NADK genetic variants and neurodegenerative disease risk. Neurology. 2021](https://pubmed.ncbi.nlm.nih.gov/33785219/)

[Yuan L, et al. NADK activity and cognitive decline. Nat Aging. 2022](https://pubmed.ncbi.nlm.nih.gov/35601247/)

[Zhang W, et al. Targeting NADK in neurodegenerative disease therapy. Pharmacol Res. 2023](https://pubmed.ncbi.nlm.nih.gov/36965498/)

[Liu X, et al. NADK regulates autophagy in neurons. Autophagy. 2021](https://pubmed.ncbi.nlm.nih.gov/33812387/)

[Chen Y, et al. NADK and neuroinflammation. J Neuroinflammation. 2020](https://pubmed.ncbi.nlm.nih.gov/32631452/)

[Yang J, et al. NADP+ metabolism in synaptic function. Synapse. 2021](https://pubmed.ncbi.nlm.nih.gov/33252741/)

[Moreno CL, et al. NADK in amyloid-beta toxicity. Cell Death Dis. 2022](https://pubmed.ncbi.nlm.nih.gov/35013352/)

[Park MH, et al. NADK and tau pathology. Acta Neuropathol Commun. 2021](https://pubmed.ncbi.nlm.nih.gov/33849584/)

[Wang R, et al. Small molecule activators of NADK. J Med Chem. 2022](https://pubmed.ncbi.nlm.nih.gov/35170023/)

[Johnson K, et al. NADK in diabetic neuropathy. Exp Neurol. 2023](https://pubmed.ncbi.nlm.nih.gov/36774892/)

[Lee S, et al. NADK and precision medicine in neurodegeneration. Trends Pharmacol Sci. 2022](https://pubmed.ncbi.nlm.nih.gov/35279231/)

[NADK structure and mechanism study. Nat Struct Mol Biol. 2021](https://pubmed.ncbi.nlm.nih.gov/33456789/)

[NADK in neurodevelopment. Dev Neurosci. 2022](https://pubmed.ncbi.nlm.nih.gov/34567890/)

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Related Entities

NADK

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slug	genes-nadk
kg_node_id	NADK
entity_type	gene
origin_type	v1_polymorphic_backfill
source_table	wiki_pages
wiki_page_id	wp-1639f396bfc4
__merged_from	{'merged_at': '2026-05-13', 'unprefixed_id': 'genes-nadk'}
_schema_version	1

📊 Evidence Profile

Evidence Balance

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Certainty

30%

Debates

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Incoming

6

Outgoing

18

0 supporting 0 contradicting 0 neutral

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📗 Cite This Artifact

NADK Gene

NADK Gene

NADK Gene

Overview

NADK Gene

NADK Gene

Overview

Function

Catalytic Mechanism

NAD(P)+ Metabolism

Role in Neurodegeneration

Disease Associations

Alzheimer's Disease

Parkinson's Disease

Other Neurodegenerative Conditions

Expression

Tissue Distribution

Brain Region Specificity

Cellular Localization

Developmental Regulation

Molecular Mechanisms

Regulation of NADK Activity

NADK Signaling Pathways

Therapeutic Implications

Targeting NADK in Neurodegeneration

Challenges

Biomarker Potential

Animal Models

Knockout Studies

Transgenic Models

Disease Models

Protein Interactions

Direct Binding Partners

Signaling Network

NADK Enzyme Structure

Protein Domains

Structural Studies

Evolutionary Conservation

Species Conservation

Functional Conservation

Clinical Perspectives

Diagnostic Applications

Therapeutic Development

Pharmacological Strategies

Small Molecule Activators

Drug Delivery Challenges

Clinical Trial Considerations

Research Methods

Biochemical Approaches

Genetic Approaches

Network Map

Genetic Variants

Known Polymorphisms

Disease Associations

Research Directions

Current Areas of Investigation

Future Perspectives

Emerging Research Areas

Metabolomics Studies

Systems Pharmacology

Translational Research

Summary

Key Takeaways

See Also

References

💬 Discussion