ADSS2 — Adenylosuccinate Synthetase 2

ADSS2 — Adenylosuccinate Synthetase 2

Overview

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">ADSS2 — Adenylosuccinate Synthetase 2</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td><strong>ADSS2</strong></td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>ADSS2 — Adenylosuccinate Synthetase 2</td>
</tr>
<tr>
<td class="label">Type</td>
<td>Gene</td>
</tr>
<tr>
<td class="label">NCBI</td>
<td><a href="https://www.ncbi.nlm.nih.gov/gene/?term=ADSS2" target="_blank">Search NCBI</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>

ADSS2 (Adenylosuccinate Synthetase 2) is a human gene encoding an enzyme essential for de novo purine nucleotide synthesis. It catalyzes the conversion of IMP (inosine monophosphate) and aspartate into adenylosuccinate, which is subsequently converted to AMP (adenosine monophosphate). This reaction is the rate-limiting step in the synthesis of adenine nucleotides and is crucial for maintaining cellular energy balance through ATP production[@adenylosuccinate].

ADSS2 is one of two ADSS isoforms in humans (ADSS1 and ADSS2), with distinct subcellular localization and tissue distribution. While ADSS1 is primarily mitochondrial, ADSS2 shows both cytosolic and mitochondrial localization, reflecting its importance in multiple cellular compartments[@adss].

Gene and Protein Structure

Gene Organization

ADSS2 — Adenylosuccinate Synthetase 2

Overview

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">ADSS2 — Adenylosuccinate Synthetase 2</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td><strong>ADSS2</strong></td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>ADSS2 — Adenylosuccinate Synthetase 2</td>
</tr>
<tr>
<td class="label">Type</td>
<td>Gene</td>
</tr>
<tr>
<td class="label">NCBI</td>
<td><a href="https://www.ncbi.nlm.nih.gov/gene/?term=ADSS2" target="_blank">Search NCBI</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>

ADSS2 (Adenylosuccinate Synthetase 2) is a human gene encoding an enzyme essential for de novo purine nucleotide synthesis. It catalyzes the conversion of IMP (inosine monophosphate) and aspartate into adenylosuccinate, which is subsequently converted to AMP (adenosine monophosphate). This reaction is the rate-limiting step in the synthesis of adenine nucleotides and is crucial for maintaining cellular energy balance through ATP production[@adenylosuccinate].

ADSS2 is one of two ADSS isoforms in humans (ADSS1 and ADSS2), with distinct subcellular localization and tissue distribution. While ADSS1 is primarily mitochondrial, ADSS2 shows both cytosolic and mitochondrial localization, reflecting its importance in multiple cellular compartments[@adss].

Gene and Protein Structure

Gene Organization

The ADSS2 gene is located on chromosome 1p31.3 and spans approximately 22 kb. It consists of 13 exons encoding a 432-amino acid protein with a molecular weight of approximately 47 kDa.

Protein Structure

ADSS2 possesses the characteristic fold of the adenylosuccinate synthetase family:

• N-terminal domain: Contains the IMP-binding site
• Central domain: Aspartate-binding region
• C-terminal domain: GTP-binding site (substrate-level phosphorylation)

Enzymatic Function

Catalytic Reaction

ADSS2 catalyzes the following reaction:
IMP + GTP + aspartate → adenylosuccinate + GDP + Pi + CO2

Adenylosuccinate is then converted to AMP and fumarate by adenylosuccinate lyase.

Regulation

ADSS2 activity is regulated by:

• Energy status: ATP feedback inhibition
• GTP levels: Substrate availability
• Protein stability: Turnover rates
• Post-translational modifications: Phosphorylation

Biological Importance

Purine Nucleotide Synthesis

Purine nucleotides (ATP, GTP) are essential for:

• Cellular energy: ATP as the primary energy currency
• Signal transduction: cAMP, GTPases
• Nucleic acid synthesis: DNA/RNA precursors
• Protein synthesis: GTP for translation
• Mitochondrial function: Oxidative phosphorylation

Energy Metabolism in the Brain

The brain has exceptionally high energy demands, consuming approximately 20% of total body oxygen despite being only 2% of body weight. Neurons depend heavily on continuous ATP supply for:

• Ion homeostasis: Na+/K+ ATPase
• Neurotransmitter cycling: Synaptic vesicle recycling
• Protein synthesis: Local translation in dendrites
• Cytoskeletal dynamics: Axonal transport

Role in Neurodegeneration

Alzheimer's Disease

ADSS2 expression and activity may be altered in [Alzheimer's disease](/diseases/alzheimers-disease) brain. The enzyme's role in ATP production becomes particularly relevant given the well-documented energy metabolism deficits in AD brains[@energya]:

The relationship between amyloid-beta and mitochondrial dysfunction may involve altered nucleotide metabolism through ADSS2[@amyloid].

Parkinson's Disease

Given the critical importance of mitochondrial function in dopaminergic [neurons](/entities/neurons), ADSS2 variants or expression changes may influence [Parkinson's disease](/diseases/parkinsons-disease) susceptibility and progression[@mitochondrial]:

Amyotrophic Lateral Sclerosis (ALS)

Energy metabolism defects are increasingly recognized in ALS pathogenesis. ADSS2 dysfunction could contribute to motor neuron vulnerability through impaired energy production[@energyb]:

Other Neurological Conditions

• Stroke/Ischemia: Energy failure is a hallmark[@ischemia]
• Aging: Declining energy metabolism[@aging]
• Epilepsy: Altered nucleotide metabolism

Expression Patterns

Tissue Distribution

ADSS2 is expressed throughout the body, with high expression in metabolically active tissues:

• Brain: High expression in neurons
• Heart: Cardiac muscle energy demands
• Skeletal muscle: High metabolic activity
• Liver: Purine biosynthesis for nucleotide pools
• Kidney: Active transport processes

Brain Regional Expression

In the brain, neurons show prominent ADSS2 expression, particularly in:

• Cortex: Pyramidal neurons
• Hippocampus: CA1-CA3 neurons
• Cerebellum: Purkinje cells
• Basal ganglia: Dopaminergic neurons
• Brainstem: Motor neurons

Cellular Localization

ADSS2 shows both cytosolic and mitochondrial localization:

• Cytosol: De novo purine synthesis
• Mitochondria:GTP import and ATP production coupling

Therapeutic Implications

Targeting Energy Metabolism

Modulating nucleotide biosynthesis pathways may have therapeutic potential in neurodegenerative diseases:

Potential Strategies

• Nucleoside supplementation: Build nucleotide pools
• Mitochondrial protectors: Maintain ADSS2 activity
• Metabolic enhancers: Improve ATP production
• Gene therapy: Increase ADSS2 expression

Research Directions

• Developing brain-penetrant nucleotide precursors
• Screening for ADSS2 activators
• Understanding isoform-specific functions
• Biomarker development for energy status

Interactions and Pathways

Related Proteins

• ADSS1: Alternative isoform with mitochondrial localization
• ATIC: Downstream enzyme in purine synthesis
• ADSL: Adenylosuccinate lyase
• IMPDH: IMP dehydrogenase (parallel pathway)

Metabolic Pathways

• De novo purine synthesis: From PRPP to IMP
• Salvage pathway: Recycling of nucleotides
• ATP synthesis: Oxidative phosphorylation
• GTP-dependent processes: Translation, signaling

Key Publications

Cross-References

• [Genes Overview](/genes)
• [Mitochondrial Dysfunction](/mechanisms/mitochondrial-dysfunction)
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Parkinson's Disease](/diseases/parkinsons-disease)
• [ALS](/diseases/amyotrophic-lateral-sclerosis)
• [Energy Metabolism](/mechanisms/energy-metabolism)

See Also

• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Parkinson's Disease](/diseases/parkinsons-disease)
• [ALS](/diseases/amyotrophic-lateral-sclerosis)
• [Mitochondrial Dysfunction](/mechanisms/mitochondrial-dysfunction)
• [Energy Metabolism](/mechanisms/energy-metabolism)
• [Purine Metabolism](/mechanisms/purine-metabolism)

External Links

• [NCBI Gene: ADSS2](https://www.ncbi.nlm.nih.gov/gene/11212)
• [UniProt: P30511](https://www.uniprot.org/uniprot/P30511)
• [GeneCards: ADSS2](https://www.genecards.org/cgi-bin/carddisp.pl?gene=ADSS2)
• [Ensembl: ENSG00000128274](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000128274)

Brain Atlas Resources

• [Allen Human Brain Atlas*: [Gene expression search](https://human.brain-map.org/microarray/search/show?search_term=ADSS2)](/datasets/allen-human-brain-atlas)
• [Allen Mouse Brain Atlas*: [Gene search](https://mouse.brain-map.org/search/index.html?query=ADSS2)](/projects/brain-atlas)
• [Allen Cell Type Atlas*: [Transcriptomic cell type reference](https://portal.brain-map.org/atlases-a](/cell-types/atlas)nd-data/rnaseq)
• BrainSpan Developmental Transcriptome: [Developmental expression](https://www.brainspan.org/rnaseq/search/index.html?search_term=ADSS2)

References