SLC7A2 (Solute Carrier Family 7 Member 2), also known as Cationic Amino Acid Transporter 2 (CAT2) or y+LAT2, is a membrane protein that mediates the transport of cationic amino acids across cell membranes[1]. This transporter plays crucial roles in various physiological processes, including nitrogen metabolism, nitric oxide synthesis, and immune responses. In the central nervous system, SLC7A2 has emerged as an important player in neuroinflammation and neurodegeneration[2].
The human SLC7A2 gene is located on chromosome 8p22 and encodes a protein of approximately 630 amino acids with a molecular weight of around 70 kDa. The gene contains multiple exons and undergoes alternative splicing to generate distinct isoforms with different tissue distribution and substrate specificities[3].
SLC7A2 exhibits a broad tissue distribution:
Two major splice variants have been characterized:
SLC7A2 belongs to the heterodimeric amino acid transporter (HAT) family. It requires interaction with a heavy chain (4F2hc/SLC3A2) for proper plasma membrane localization and function. The transporter operates as an exchange system, facilitating the bidirectional movement of cationic amino acids in exchange for neutral amino acids.
SLC7A2-mediated arginine transport is critical for nitric oxide (NO) production by neuronal nitric oxide synthase (nNOS)[7]. Arginine serves as the substrate for nNOS, which generates NO as a signaling molecule in various neurological processes. Dysregulation of this pathway has been implicated in:
Research has shown altered SLC7A2 expression in the brains of APP/PS1 transgenic mouse models of Alzheimer's disease[8]. The changes include:
SLC7A2 has been implicated in multiple sclerosis pathogenesis through its role in immune cell function and neuroinflammation[2:1]. The transporter influences:
While less studied, SLC7A2 may play a role in Parkinson's disease through:
Inflammatory stimuli dramatically upregulate SLC7A2 expression in the brain[9]. This induction is mediated by:
The upregulation serves to:
SLC7A2 represents a potential therapeutic target for:
Several strategies are being explored:
SLC7A2 interacts with multiple signaling pathways:
| Pathway | Interaction | Effect |
|---|---|---|
| mTOR | Regulation by mTORC1 | Modulates translation |
| NF-κB | Cytokine-induced expression | Neuroinflammation |
| MAPK | Signaling downstream of NO | Cell survival/death |
| PI3K/Akt | Cross-talk | Neuronal survival |
SLC7A2 knockout mice exhibit:
Overexpression studies reveal:
SLC7A2 orthologs have been identified across species:
The evolutionary conservation underscores the fundamental importance of cationic amino acid transport in nervous system function.
The study of SLC7A2 employs various approaches:
Key questions remaining include:
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Sattler R, Rothstein JD. Regulation of y+ LAT-1 and y+ LAT-2 in brain disease. Neurobiol Dis. 2020. ↩︎ ↩︎
Devés R, Boyd CA. Transporters for cationic amino acids in animal cells: structure, function, and regulation. Physiol Rev. 1998. ↩︎
Bertz M, Burckhardt BB. Y+ LAT-2 and y+ LAT-1 amino acid transporters in brain endothelial cells. Fluids Barriers CNS. 2014. ↩︎
Silbernagl S, Despopoulos A. Renal transport of amino acids. Physiology. 2003. ↩︎
Simmons WW, Closs EI, Cunningham JM, Smith TW, Kelly RA. Cytokines and insulin induce cationic amino acid transporter (CAT) expression in cardiac myocytes. J Biol Chem. 1996. ↩︎
Schwartz PM, Mearow BA, Skupa PJ, Fine RE. Macrophage-conditioned medium increases neuronal neuronal nitric oxide synthase expression and activity in motor neurons. Neuroreport. 2003. ↩︎
Liu CY, Yang Y, Wang L, Liu J, Tan X, Sun Z. Altered expression of cationic amino acid transporter 2 in the brain of APP/PS1 transgenic mice. J Neurosci Res. 2018. ↩︎
Williams JB, Ghosh-Leblanc S, Chan J, Nguyen QP, Yeung SY, Lee M. Induction of cationic amino acid transporters in brain during inflammation. J Neurochem. 2005. ↩︎
Kim J, Lee Y, Lee J, Kim S, Park K. System L amino acid transporter LAT1 mediates amino acid uptake in glioma cells. J Neurochem. 2019. ↩︎