SLC7A1 Gene
<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">SLC7A1 Gene</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>SLC7A1</td>
</tr>
<tr>
<td class="label">Official Full Name</td>
<td>Solute Carrier Family 7 Member 1</td>
</tr>
<tr>
<td class="label">Alias</td>
<td>CAT1, CAT-1, ATRC1</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>19p13.2</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>6541</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000147614</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>P30825</td>
</tr>
<tr>
<td class="label">Transcript Length</td>
<td>~4.2 kb</td>
</tr>
<tr>
<td class="label">Exon Count</td>
<td>14 exons</td>
</tr>
<tr>
<td class="label">Amino Acid</td>
<td>Affinity (Km)</td>
</tr>
<tr>
<td class="label">L-Arginine</td>
<td>~100 μM</td>
</tr>
<tr>
<td class="label">L-Lysine</td>
<td>~150 μM</td>
</tr>
<tr>
<td class="label">L-Ornithine</td>
<td>~200 μM</td>
</tr>
<tr>
<td class="label">L-Histidine</td>
<td>~500 μM</td>
</tr>
<tr>
<td class="label">Approach</td>
<td>Evidence</td>
</tr>
<tr>
<td class="label">L-arginine supplementation</td>
<td>Cognitive improvement in AD models</td>
</tr>
<tr>
<td class="label">L-ornithine supplementation</td>
<td>Enhanced polyamine synthesis</td>
</tr>
<tr>
<td class="label">Arginine + antioxidants</td>
<td>Combined neuroprotection</td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">21 edges</a></td>
</tr>
</table>
Overview
Mermaid diagram (expand to render)
SLC7A1 (Solute Carrier Family 7 Member 1), also known as CAT-1 (Cationic Amino Acid Transporter 1), is a high-affinity transmembrane transporter that mediates cellular uptake of cationic amino acids, particularly L-arginine, L-lysine, and L-ornithine["@mann2003"]. This transporter plays critical roles in nitric oxide synthesis, polyamine production, and neurotransmitter regulation in the brain, making it highly relevant to neurodegenerative disease research.
As the major cationic amino acid transporter in the central nervous system, SLC7A1 is essential for maintaining arginine availability for multiple critical pathways including nitric oxide (NO) synthesis, creatine biosynthesis, and neurotransmitter metabolism. Dysregulation of SLC7A1 has been implicated in both Alzheimer's and Parkinson's diseases.
Gene Structure and Expression
Genomic Organization
Protein Structure
SLC7A1 encodes a 629-amino acid membrane protein with 14 transmembrane domains. The protein features:
- N-terminal extracellular domain: Contains glycosylation sites
- Transmembrane helices: 14 membrane-spanning regions
- C-terminal intracellular domain: Contains regulatory motifs
- Substrate binding site: Central channel for cation transport
The transporter requires heterodimerization with SLC3A1 (4F2hc) for proper trafficking to the plasma membrane. This heterodimer complex is essential for functional expression.
Normal Biological Functions
Amino Acid Transport
SLC7A1 transports cationic amino acids with distinct kinetics[@closs1996]:
The transporter operates as a facilitated diffusion system, allowing bidirectional transport depending on concentration gradients. Under physiological conditions, net uptake of arginine occurs.
Nitric Oxide Synthesis
Arginine is the sole substrate for nitric oxide synthase (NOS), making SLC7A1 critical for NO production:
- Endothelial NOS (eNOS): Vascular tone regulation
- Neuronal NOS (nNOS): Neurotransmission
- Inducible NOS (iNOS): Immune response
NO dysregulation contributes to neurovascular dysfunction in neurodegenerative diseases[@van2020].
Polyamine Synthesis
Arginine serves as the precursor for polyamine biosynthesis:
- Ornithine → Putrescine → Spermidine → Spermine
- Critical for neuronal survival
- Involved in synaptic plasticity
- Protects against oxidative stress
SLC7A1 indirectly affects neurotransmitter metabolism:
- Arginine is a precursor for agmatine
- Involved in creatine biosynthesis
- Supports dopamine metabolism
Expression in Brain
Regional Distribution
SLC7A1 shows region-specific expression in the brain[@kakigi2014]:
- Highest expression: Cerebral cortex, hippocampus
- Moderate expression: Cerebellum, basal ganglia
- Lower expression: Thalamus, hypothalamus
Cell Type Expression
- Neurons: High expression in pyramidal neurons
- Endothelial cells: Blood-brain barrier
- Astrocytes: Perivascular astrocyte end-feet
- Microglia: Moderate expression
Developmental Expression
SLC7A1 expression changes during development:
- Low expression in embryonic brain
- Peaks during postnatal development
- Maintained in adult brain
- Decreases with age
Role in Neurodegeneration
Alzheimer's Disease
Multiple studies link SLC7A1 to AD pathogenesis:
L-Arginine Transport Deficiency
- Reduced SLC7A1 expression in AD brain[@gulys2015]
- Impaired arginine uptake in AD neurons
- Decreased NO production
- Reduced polyamine levels
Neurovascular Dysfunction
SLC7A1-mediated arginine transport supports neurovascular coupling[@van2020]:
- Endothelial arginine uptake for NO synthesis
- Blood flow regulation
- Blood-brain barrier maintenance
- Cerebral perfusion
Therapeutic Implications
L-arginine supplementation has shown promise in AD models[@huang2020]:
- Improved cognitive function
- Enhanced synaptic plasticity
- Reduced oxidative stress
- Neuroprotective effects
Parkinson's Disease
SLC7A1 alterations in PD models have been reported[@li2003]:
- Altered cationic amino acid transport
- Reduced arginine availability
- Impaired NO synthesis
- Dopaminergic neuron vulnerability
Mechanisms
- Mitochondrial dysfunction linked to arginine deficiency
- NO signaling impairment
- Polyamine depletion
- Oxidative stress vulnerability
Other Neurodegenerative Conditions
- Stroke: Reduced SLC7A1 in ischemic tissue
- Amyotrophic lateral sclerosis: Motor neuron vulnerability
- Huntington's disease: Polyamine pathway alterations
Therapeutic Targeting
Arginine Supplementation
Transport Modulation
- Small molecule SLC7A1 activators
- Heterodimer stabilization
- Regulatory pathway targeting
Biomarkers
- Arginine levels in CSF
- NO metabolites
- Polyamine levels
Animal Models
Knockout Mice
SLC7A1 knockout mice display:
- Embryonic lethality (complete knockout)
- Urea cycle abnormalities
- Growth retardation
- Neurological deficits
Conditional Knockout
Brain-specific knockout shows:
- Impaired NO synthesis
- Behavioral abnormalities
- Synaptic dysfunction
- Learning deficits
Transgenic Overexpression
Motor neuron-specific overexpression:
- Protection in disease models
- Enhanced amino acid uptake
- Improved function
Clinical Considerations
Biomarkers
- Plasma arginine levels
- NO metabolites in CSF
- Polyamine measurements
Therapeutic Approaches
- Dietary arginine supplementation
- Polyamine administration
- NO donors (caution needed)
Drug Interactions
- Arginine competes with lysine for transport
- NOS inhibitors affect downstream pathways
- Polyamine synthesis intermediates
Key Publications
[Closs et al., Membrane topology of CAT-1 (1996)](https://pubmed.ncbi.nlm.nih.gov/8825383/)
[Mann et al., Structure and function of CATs (2003)](https://pubmed.ncbi.nlm.nih.gov/12517427/)
[Schneider et al., hCAT-1 in endothelial cells (2001)](https://pubmed.ncbi.nlm.nih.gov/11561020/)
[Shin et al., Neuronal expression of CAT-1 (2006)](https://pubmed.ncbi.nlm.nih.gov/16739021/)
[Huang et al., L-arginine and cognitive function (2020)](https://pubmed.ncbi.nlm.nih.gov/32920468/)
[Gulyás et al., PET imaging of hCAT (2015)](https://pubmed.ncbi.nlm.nih.gov/25669902/)
[Li et al., Cationic amino acid transporters in PD (2003)](https://pubmed.ncbi.nlm.nih.gov/14552890/)
External Links
- [NCBI Gene: SLC7A1](https://www.ncbi.nlm.nih.gov/gene/6541)
- [UniProt: P30825](https://www.uniprot.org/uniprot/P30825)
- [GeneCards: SLC7A1](https://www.genecards.org/cgi-bin/carddisp.pl?gene=SLC7A1)
- [OMIM: 104615](https://www.omim.org/entry/104615)
See Also
- [Genes Index](/genes)
- [SLC Family](/proteins/slc-transporters)
- [Nitric Oxide Mechanisms](/mechanisms/nitric-oxide)
- [Alzheimer's Disease](/diseases/alzheimers-disease)
- [Parkinson's Disease](/diseases/parkinsons-disease)
Pathway Diagram
The following diagram shows the key molecular relationships involving SLC7A1 Gene discovered through SciDEX knowledge graph analysis:
Mermaid diagram (expand to render)