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[1]. 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.
| Property | Value |
|---|---|
| Gene Symbol | SLC7A1 |
| Official Full Name | Solute Carrier Family 7 Member 1 |
| Alias | CAT1, CAT-1, ATRC1 |
| Chromosomal Location | 19p13.2 |
| NCBI Gene ID | 6541 |
| Ensembl ID | ENSG00000147614 |
| UniProt ID | P30825 |
| Transcript Length | ~4.2 kb |
| Exon Count | 14 exons |
SLC7A1 encodes a 629-amino acid membrane protein with 14 transmembrane domains. The protein features:
The transporter requires heterodimerization with SLC3A1 (4F2hc) for proper trafficking to the plasma membrane. This heterodimer complex is essential for functional expression.
SLC7A1 transports cationic amino acids with distinct kinetics[2]:
| Amino Acid | Affinity (Km) | Transport Rate |
|---|---|---|
| L-Arginine | ~100 μM | High |
| L-Lysine | ~150 μM | Moderate |
| L-Ornithine | ~200 μM | Moderate |
| L-Histidine | ~500 μM | Low |
The transporter operates as a facilitated diffusion system, allowing bidirectional transport depending on concentration gradients. Under physiological conditions, net uptake of arginine occurs.
Arginine is the sole substrate for nitric oxide synthase (NOS), making SLC7A1 critical for NO production:
NO dysregulation contributes to neurovascular dysfunction in neurodegenerative diseases[3].
Arginine serves as the precursor for polyamine biosynthesis:
SLC7A1 indirectly affects neurotransmitter metabolism:
SLC7A1 shows region-specific expression in the brain[4]:
SLC7A1 expression changes during development:
Multiple studies link SLC7A1 to AD pathogenesis:
SLC7A1-mediated arginine transport supports neurovascular coupling[3:1]:
L-arginine supplementation has shown promise in AD models[6]:
SLC7A1 alterations in PD models have been reported[7]:
| Approach | Evidence | Status |
|---|---|---|
| L-arginine supplementation | Cognitive improvement in AD models | Preclinical |
| L-ornithine supplementation | Enhanced polyamine synthesis | Research |
| Arginine + antioxidants | Combined neuroprotection | Research |
SLC7A1 knockout mice display:
Brain-specific knockout shows:
Motor neuron-specific overexpression:
Mann GE, Yudilevich DL, Sobrevia L. Structure and function of cationic amino acid transporters (CATs). Physiol Rev. 2003. ↩︎
Closs EI, Bode BM, Gräfer S, Böhme A, Blume R, Cash S. Membrane topology of the human cationic amino acid transporter (human CAT-1). J Mol Neurosci. 1996. ↩︎
van Wijk N, Rijntjes E, van de Poll MC, Sastre M, Wurtman RJ, Watkins CJ, Platt B, Biesemann L, Broersen LM. Cerebral blood flow and neurovascular coupling in aging and Alzheimer's disease. J Cereb Blood Flow Metab. 2020. ↩︎ ↩︎
Kakigi T, Nakai K, Goto Y, Ishikawa A, Enomoto S, Takeda K, Nishiyama M, Kato Y. Expression of CAT-1 in the mouse brain during development. Neuroscience. 2014. ↩︎
Gulyás B, Hendrik J, Varrone A, Nag S, Lehel S, Tóth M, Khan IS, Oikonen V, Långström B, Rim AJ, Halldin C. PET imaging of the cationic amino acid transporter (hCAT) in the human brain. J Cereb Blood Flow Metab. 2015. ↩︎
Huang Y, Zai M, Zhao D, Yao Y, Tang Y, Liu J, Wu J. L-arginine improves cognitive function and synaptic plasticity in an aged rat model of sporadic Alzheimer's disease. Aging Dis. 2020. ↩︎
Li H, Cashion DK, Myers LM, Thöny B, Ayling J, Ratcliffe PJ, Gleadall W. Altered expression of cationic amino acid transporters in Parkinson's disease. Exp Neurol. 2003. ↩︎