large neutral amino acids transporter small subunit 1; L-type amino acid transporter 1; solute carrier family 7 member 5; y+ system cationic amino acid transporter; 4F2 light chain; 4F2 LC; 4F2LC; CD98 light chain; integral membrane protein E16; hLAT1 (SLC7A5, CD98LC, LAT1, MPE16)

Function: - Na⁺-independent, high-affinity transport of large neutral amino acids such as phenylalanine, tyrosine, leucine, arginine & tryptophan, when associated with SLC3A2 - involved in cellular amino acid uptake - acts as an amino acid exchanger - involved in the transport of L-DOPA across the blood-brain barrier, & that of thyroid hormones triiodothyronine (T3) & thyroxine (T4) across the cell membrane in tissues such as placenta - plays a role in neuronal cell proliferation (neurogenesis) in brain - involved in uptake of methylmercury (MeHg) as L-cysteine D,L-homocysteine complex, thus plays a role in metal ion homeostasis & toxicity - role in cellular activity of small molecular weight nitrosothiols, via the stereoselective transport of L-nitrosocysteine (L-CNSO) across the transmembrane - mediates blood-to-retina L-leucine transport across the inner blood-retinal barrier which in turn may play a role in maintaining large neutral amino acids as well as neurotransmitters in the neural retina - acts as the major transporter of tyrosine in fibroblasts - disulfide-linked heterodimer with amino acid transport protein SLC3A2 Kinetic parameters: - KM=7.9 uM for T4 - KM=0.8 uM for T3 - KM=12.5 uM for rT3 - KM=7.9 uM for 3,3'-diiodothyronine - KM=46 uM for leucine - KM=19 uM for tryptophan - KM=32 uM for L-leucine - KM=10 mM for L-alanine - KM=2.2 mM for L-glutamine - KM=35 uM for L-histidine - KM=740 uM for L-phenylalanine - KM=98 uM for MeHg-L-cysteine - KM=99 uM for methionine * Kinetic parameters may be affected by cell type & presence of choline chloride Structure: - belongs to the amino acid-polyamine-organocation (APC) superfamily, L-type amino acid transporter (LAT) (TC 2.A.3.8) family Compartment: - cytoplasm, cytosol - apical cell membrane multi-pass membrane protein - localized to plasma membrane by SLC3A2 - localized to the apical membrane of placental syncytiophoblastic cells - expressed in both luminal & abluminal membranes of brain capillary endothelial cells (putative) Expression: 1) expressed abundantly in adult lung, liver, brain, skeletal muscle, placenta, bone marrow, testis, resting lymphocytes & monocytes, & in fetal liver 2) weaker expression in thymus, cornea, retina, peripheral leukocytes, spleen, kidney, colon & lymph node 3) during gestation, expression in the placenta is stronger at full-term than during earlier gestation 4) expressed in all human tumor cell lines tested & in the astrocytic process of primary astrocytic gliomas 5) expressed in retinal endothelial cells & in the intestinal epithelial cell line Caco-2 6) expression induced in quiescent peripheral blood lymphocytes after treatment with PMA (phorbol myristate acetate)/ PHA (phytohemagglutinin) Pathology: - may play a role in high-grade gliomas

General

glycoprotein phosphoprotein solute carrier family 7 (SLC7, SLC7A) transmembrane 12 protein

Properties

SIZE: entity length = 507 aa MW = 55 kD COMPARTMENT: cytoplasm MOTIF: Ser phosphorylation site {S35} N-glycosylation site {N49} transmembrane domain {50-70} transmembrane domain {84-104} transmembrane domain {120-140} transmembrane domain {146-166} transmembrane domain {170-190} transmembrane domain {199-219} N-glycosylation site {N230} transmembrane domain {243-263} transmembrane domain {274-294} transmembrane domain {319-339} N-glycosylation site {N340} transmembrane domain {396-416} transmembrane domain {431-451} transmembrane domain {458-478} Thr phosphorylation site {T507}

Database Correlations

OMIM 600182 UniProt Q01650 Pfam PF00324 Entrez Gene 8140 Kegg hsa:8140

References

UniProt :accession Q01650