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MGP003461

UniProt Annotations

Entry Information

Gene Name	solute carrier family 7 (amino acid transporter light chain, L system), member 5
Protein Entry	LAT1_HUMAN
UniProt ID	Q01650
Species	Human

Comments

Comment type	Description
Biophysicochemical Properties	Kinetic parameters: KM=7.9 uM for T4 (in the presence of choline chloride) {ECO:0000269\|PubMed:10574970, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:12117417, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:18262359}; KM=0.8 uM for T3 (in the presence of choline chloride) {ECO:0000269\|PubMed:10574970, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:12117417, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:18262359}; KM=12.5 uM for reverse triiodothyronine (rT3) (in the presence of choline chloride) {ECO:0000269\|PubMed:10574970, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:12117417, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:18262359}; KM=7.9 uM for 3,3'-diiodothyronine (in the presence of choline chloride) {ECO:0000269\|PubMed:10574970, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:12117417, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:18262359}; KM=46 uM for leucine (in the presence of choline chloride) {ECO:0000269\|PubMed:10574970, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:12117417, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:18262359}; KM=19 uM for tryptophan (in the presence of choline chloride) {ECO:0000269\|PubMed:10574970, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:12117417, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:18262359}; KM=32 uM for L-leucine {ECO:0000269\|PubMed:10574970, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:12117417, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:18262359}; KM=10 mM for L-alanine {ECO:0000269\|PubMed:10574970, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:12117417, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:18262359}; KM=2.2 mM for L-glutamine {ECO:0000269\|PubMed:10574970, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:12117417, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:18262359}; KM=35 uM for L-histidine {ECO:0000269\|PubMed:10574970, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:12117417, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:18262359}; KM=740 uM for L-phenylalanine {ECO:0000269\|PubMed:10574970, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:12117417, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:18262359}; KM=98 uM for MeHg-L-cysteine {ECO:0000269\|PubMed:10574970, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:12117417, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:18262359}; KM=99 uM for methionine {ECO:0000269\|PubMed:10574970, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:12117417, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:18262359}; KM=55.2 uM for phenylalanine (in T24 human bladder carcinoma cells) {ECO:0000269\|PubMed:10574970, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:12117417, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:18262359}; KM=60.4 uM for tyrosine (in T24 human bladder carcinoma cells) {ECO:0000269\|PubMed:10574970, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:12117417, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:18262359}; KM=16.4 uM for tyrosine (in human fibroblasts) {ECO:0000269\|PubMed:10574970, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:12117417, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:18262359}; KM=138 uM for Dopa (in T24 human bladder carcinoma cells) {ECO:0000269\|PubMed:10574970, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:12117417, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:18262359}; KM=96.5 uM for 3-O-methyldopa (in T24 human bladder carcinoma cells) {ECO:0000269\|PubMed:10574970, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:12117417, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:18262359}; KM=153 uM for alpha-methyltyrosine (in T24 human bladder carcinoma cells) {ECO:0000269\|PubMed:10574970, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:12117417, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:18262359}; KM=216 uM for alpha-methyldopa (in T24 human bladder carcinoma cells) {ECO:0000269\|PubMed:10574970, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:12117417, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:18262359}; KM=191 uM for gabapentin (in T24 human bladder carcinoma cells) {ECO:0000269\|PubMed:10574970, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:12117417, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:18262359}; KM=7.3 uM for triiodothyronine (in T24 human bladder carcinoma cells) {ECO:0000269\|PubMed:10574970, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:12117417, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:18262359}; KM=162 uM for thyroxine (in T24 human bladder carcinoma cells) {ECO:0000269\|PubMed:10574970, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:12117417, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:18262359}; KM=75.3 uM for melphanan (in T24 human bladder carcinoma cells) {ECO:0000269\|PubMed:10574970, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:12117417, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:18262359}; KM=156 uM for BCH (in T24 human bladder carcinoma cells) {ECO:0000269\|PubMed:10574970, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:12117417, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:18262359};
Function	Sodium-independent, high-affinity transport of large neutral amino acids such as phenylalanine, tyrosine, leucine, arginine and tryptophan, when associated with SLC3A2/4F2hc. Involved in cellular amino acid uptake. Acts as an amino acid exchanger. Involved in the transport of L-DOPA across the blood- brain barrier, and that of thyroid hormones triiodothyronine (T3) and thyroxine (T4) across the cell membrane in tissues such as placenta. Plays a role in neuronal cell proliferation (neurogenesis) in brain. Involved in the uptake of methylmercury (MeHg) when administered as the L-cysteine or D,L-homocysteine complexes, and hence plays a role in metal ion homeostasis and toxicity. Involved in the cellular activity of small molecular weight nitrosothiols, via the stereoselective transport of L- nitrosocysteine (L-CNSO) across the transmembrane. May play an important role in high-grade gliomas. Mediates blood-to-retina L- leucine transport across the inner blood-retinal barrier which in turn may play a key role in maintaining large neutral amino acids as well as neurotransmitters in the neural retina. Acts as the major transporter of tyrosine in fibroblasts. {ECO:0000269\|PubMed:10049700, ECO:0000269\|PubMed:10391915, ECO:0000269\|PubMed:10574970, ECO:0000269\|PubMed:11311135, ECO:0000269\|PubMed:11389679, ECO:0000269\|PubMed:11557028, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:11742812, ECO:0000269\|PubMed:12117417, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:15769744, ECO:0000269\|PubMed:16496379, ECO:0000269\|PubMed:18262359, ECO:0000269\|PubMed:9751058}.
Induction	Expression induced in quiescent peripheral blood lymphocytes after treatment with phorbol myristate acetate (PMA) and phytohemagglutinin (PHA). Expression and the uptake of leucine is stimulated in mononuclear, cytotrophoblast-like choriocarcinoma cells by combined treatment with PMA and calcium ionophore. {ECO:0000269\|PubMed:11742812, ECO:0000269\|PubMed:1597461}.
Miscellaneous	The uptake of leucine, tyrosine and tryptophan is inhibited by the different iodothyronines, in particular T3. Leucine transport is also inhibited by small zwitterionic amino acids (i.e. glycine, alanine, serine, threonine and cysteine) and by glutamine and asparginine. The uptake of T3 is almost completely blocked by coincubation with leucine, tryptophan, tyrosine, and phenylalanine, or 2-amino-bicyclo-(2,2,1)-heptane-2- carboxylate (BCH). Methionine uptake was inhibited by the L-system substrates L-leucine, BCH, L-cysteine and by the MeHg-L-cysteine complex and structurally related S-ethyl-L-cysteine. MeHg-L- cysteine uptake is inhibited by L-methionine, L-leucine, BCH and S-ethyl-L-cysteine. L-leucine uptake was inhibited by L-CNSO. Tyrosine uptake in fibroblasts was inhibited by D-methionine, and methyl-aminoisobutyric acid (MeAIB).
Similarity	Belongs to the amino acid-polyamine-organocation (APC) superfamily. L-type amino acid transporter (LAT) (TC 2.A.3.8) family. {ECO:0000305}.
Subcellular Location	Cytoplasm, cytosol. Apical cell membrane; Multi-pass membrane protein. Note=Located to the plasma membrane by SLC3A2/4F2hc. Localized to the apical membrane of placental syncytiophoblastic cells. Expressed in both luminal and abluminal membranes of brain capillary endothelial cells (By similarity). {ECO:0000250}.
Subunit	Disulfide-linked heterodimer with the amino acid transport protein SLC3A2/4F2hc. {ECO:0000269\|PubMed:10049700, ECO:0000269\|PubMed:11311135, ECO:0000269\|PubMed:11389679, ECO:0000269\|PubMed:11557028, ECO:0000269\|PubMed:11564694, ECO:0000269\|PubMed:12225859, ECO:0000269\|PubMed:15769744, ECO:0000269\|PubMed:9751058}.
Tissue Specificity	Expressed abundantly in adult lung, liver, brain, skeletal muscle, placenta, bone marrow, testis, resting lymphocytes and monocytes, and in fetal liver. Weaker expression in thymus, cornea, retina, peripheral leukocytes, spleen, kidney, colon and lymph node. During gestation, expression in the placenta was significantly stronger at full-term than at the mid-trimester stage. Also expressed in all human tumor cell lines tested and in the astrocytic process of primary astrocytic gliomas. Expressed in retinal endothelial cells and in the intestinal epithelial cell line Caco-2. {ECO:0000269\|PubMed:10049700, ECO:0000269\|PubMed:10072483, ECO:0000269\|PubMed:11389679, ECO:0000269\|PubMed:11557028, ECO:0000269\|PubMed:11742812, ECO:0000269\|PubMed:12824232, ECO:0000269\|PubMed:1597461, ECO:0000269\|PubMed:16027961, ECO:0000269\|PubMed:16496379}.