Heterodimeric amino-acid transporters are a family of transport proteins that facilitate the transport of certain amino acids across cell membranes.[1] Each comprises a light and a heavy protein subunit. Transport activity happens in the light.
The following table lists the members of this family:
| Transport system | Light subunit | Heavy subunit | Tissue distribution | Substrates | Affinity | Sodium dependence | Disease linkage | |
|---|---|---|---|---|---|---|---|---|
| L | LAT1 (SLC7A5) | 4F2hc (SLC3A2) | kidney, liver, intestine, brain, heart lung, blood–brain barrier | large neutral amino acids, thyroid hormones | micromolar | no | – | |
| L | LAT2 (SLC7A8) | 4F2hc (SLC3A2) | kidney, intestine, brain, liver, muscle, heart, lung | smaller neutral amino acids | millimolar | no | – | |
| y+L | y+LAT1 (SLC7A7) | 4F2hc (SLC3A2) | kidney, intestine, lung, erythrocytes, leukocytes | large neutral amino acids, dibasic amino acid exchange | micromolar | yes | Lysinuric protein intolerance | |
| y+L | y+LAT2 (SLC7A6) | 4F2hc (SLC3A2) | brain, intestine, heart, kidney, lung, liver | neutral amino acids, dibasic amino acid exchange, glutamine/arginine exchange | millimolar | yes | – | |
| xc− | xCT (SLC7A11) | 4F2hc (SLC3A2) | macrophages, liver, kidney, brain | glutamine/cystine exchange | no | – | ||
| asc | ascAT1 (SLC7A10) | 4F2hc (SLC3A2) | brain, lung, small intestine, kidney | small neutral amino acids | no | – | ||
| b0,+ | b0,+AT1 (SLC7A9) | rBAT (SLC3A1) | kidney, intestine, brain | neutral/dibasic amino acids | no | Cystinuria type I |