Abstract
The CAT proteins (CAT for cationic amino acid transporter) are amongst the first mammalian amino acid transporters identified on the molecular level and seem to be the major entry path for cationic amino acids in most cells. However, CAT proteins mediate also efflux of their substrates and thus may also deplete cells from cationic amino acids under certain circumstances. The CAT proteins form a subfamily of the solute carrier family 7 (SLC7) that consists of four confirmed transport proteins for cationic amino acids: CAT-1 (SLC7A1), CAT-2A (SLC7A2A), CAT-2B (SLC7A2B), and CAT-3 (SLC7A3). SLC7A4 and SLC7A14 are two related proteins with yet unknown function. One focus of this review lies on structural and functional differences between the different CAT isoforms. The expression of the CAT proteins is highly regulated on the level of transcription, mRNA stability, translation and subcellular localization. Recent advances toward a better understanding of these mechanisms provide a second focus of this review.
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Abbreviations
- CAT:
-
cationic amino acid transporter, prefix h, r, m: human, rat and mouse, respectively
- HAT:
-
heteromeric amino acid transporter
- DC:
-
dendritic cell
- HEK:
-
human embryonic kidney cells
- IRES:
-
internal ribosomal entry sequence
- NOS:
-
nitric oxide synthase, prefix e, and i: endothelial and inducible isoform, respectively
- PAEC:
-
porcine aortic endothelial cells
- PKC:
-
protein kinase C
- SLC:
-
solute carrier family
- TM:
-
transmembrane domain
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Acknowledgement
The work in the authors laboratory is supported by Grants Cl 100/4-1 and the Collaborative Research Center SFB 553 (Project B4) from the Deutsche Forschungsgemeinschaft, Bonn, Germany.
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Closs, E., Boissel, JP., Habermeier, A. et al. Structure and Function of Cationic Amino Acid Transporters (CATs). J Membrane Biol 213, 67–77 (2006). https://doi.org/10.1007/s00232-006-0875-7
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DOI: https://doi.org/10.1007/s00232-006-0875-7
Keywords
- Amino acid starvation
- Amino acid responsive element
- Cationic amino acid transporter
- IRES
- micro RNA
- Nitric oxide
- Paraspeckles
- SLC7
- System y+