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MGP002858

UniProt Annotations

Entry Information
Gene Namesolute carrier family 3 (amino acid transporter heavy chain), member 2
Protein Entry4F2_HUMAN
UniProt IDP08195
SpeciesHuman
Comments
Comment typeDescription
Alternative ProductsEvent=Alternative splicing; Named isoforms=4; Name=1; IsoId=P08195-1; Sequence=Displayed; Name=2; IsoId=P08195-2; Sequence=VSP_037907; Name=3; IsoId=P08195-3; Sequence=VSP_037908; Name=4; IsoId=P08195-4; Sequence=VSP_037909;
Biophysicochemical PropertiesKinetic parameters: KM=295 uM for glutamine (in the presence of NaCl) {ECO:0000269|PubMed:10903140}; KM=236 uM for leucine (in the presence of NaCl) {ECO:0000269|PubMed:10903140}; KM=120 uM for arginine (in the presence of NaCl) {ECO:0000269|PubMed:10903140}; KM=138 uM for arginine (in the absence of NaCl) {ECO:0000269|PubMed:10903140};
FunctionRequired for the function of light chain amino-acid transporters. Involved in sodium-independent, high-affinity transport of large neutral amino acids such as phenylalanine, tyrosine, leucine, arginine and tryptophan. Involved in guiding and targeting of LAT1 and LAT2 to the plasma membrane. When associated with SLC7A6 or SLC7A7 acts as an arginine/glutamine exchanger, following an antiport mechanism for amino acid transport, influencing arginine release in exchange for extracellular amino acids. Plays a role in nitric oxide synthesis in human umbilical vein endothelial cells (HUVECs) via transport of L-arginine. Required for normal and neoplastic cell growth. When associated with SLC7A5/LAT1, is also 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. 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. When associated with SLC7A5 or SLC7A8, involved in the cellular activity of small molecular weight nitrosothiols, via the stereoselective transport of L- nitrosocysteine (L-CNSO) across the transmembrane. Together with ICAM1, regulates the transport activity LAT2 in polarized intestinal cells, by generating and delivering intracellular signals. When associated with SLC7A5, plays an important role in transporting L-leucine from the circulating blood to the retina across the inner blood-retinal barrier. {ECO:0000269|PubMed:10903140, 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:12716892, ECO:0000269|PubMed:14603368, ECO:0000269|PubMed:15769744, ECO:0000269|PubMed:15980244, ECO:0000269|PubMed:9751058, ECO:0000269|PubMed:9829974, ECO:0000269|PubMed:9878049}.
InductionExpression is induced in resting peripheral blood T- lymphocytes following PHA stimulation. Expression increases at the time of maximal DNA synthesis, in fibroblasts stimulated to divide. 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:3265470, ECO:0000269|PubMed:3480538}.
Mass SpectrometryMass=57944.93; Method=MALDI; Range=1-529; Evidence={ECO:0000269|PubMed:11840567};
MiscellaneousArginine uptake is inhibited by increasing concentrations of leucine in the presence of Na(+).
PtmPhosphorylation on Ser-406; Ser-408 or Ser-410 and on Ser-527 or Ser-531 by ecto-protein kinases favors heterotypic cell-cell interactions. {ECO:0000269|PubMed:19065266, ECO:0000269|PubMed:19690332, ECO:0000269|PubMed:21406692}.
SimilarityBelongs to the SLC3A transporter family. {ECO:0000305}.
Subcellular LocationApical cell membrane; Single-pass type II membrane protein. Melanosome. Note=Identified by mass spectrometry in melanosome fractions from stage I to stage IV. Localized to the plasma membrane when associated with SLC7A5 or SLC7A8. Localized to the placental apical membrane. Located selectively at cell-cell adhesion sites (By similarity). Colocalized with SLC7A8/LAT2 at the basolateral membrane of kidney proximal tubules and small intestine epithelia. Expressed in both luminal and abluminal membranes of brain capillary endothelial cells (By similarity). {ECO:0000250}.
SubunitDisulfide-linked heterodimer of a glycosylated heavy chain and a non-glycosylated light chain (SLC7A5, SLC7A6, SLCA7A7, SLC7A8, SLC7A10 or SLCA7A11). Colocalizes with cadherins (By similarity). Interacts with FAM57A/CT120 and ICAM1. Constitutively and specifically associates with beta-1 integrins (alpha-2/beta-1, alpha-3/beta-1, alpha-5/beta-1 and alpha-6/beta-1), but minimally with alpha-4/beta-1. {ECO:0000250, ECO:0000269|PubMed:11311135, ECO:0000269|PubMed:11389679, ECO:0000269|PubMed:11557028, ECO:0000269|PubMed:11564694, ECO:0000269|PubMed:11696247, ECO:0000269|PubMed:12225859, ECO:0000269|PubMed:12270127, ECO:0000269|PubMed:12716892, ECO:0000269|PubMed:14603368, ECO:0000269|PubMed:15769744, ECO:0000269|PubMed:17724034, ECO:0000269|PubMed:9751058, ECO:0000269|PubMed:9829974, ECO:0000269|PubMed:9878049}.
Tissue SpecificityExpressed ubiquitously in all tissues tested with highest levels detected in kidney, placenta and testis and weakest level in thymus. During gestation, expression in the placenta was significantly stronger at full-term than at the mid- trimester stage. Expressed in HUVECS and at low levels in resting peripheral blood T-lymphocytes and quiescent fibroblasts. Also expressed in fetal liver and in the astrocytic process of primary astrocytic gliomas. Expressed in retinal endothelial cells and in the intestinal epithelial cell line C2BBe1. {ECO:0000269|PubMed:11389679, ECO:0000269|PubMed:11557028, ECO:0000269|PubMed:11742812, ECO:0000269|PubMed:12716892, ECO:0000269|PubMed:14603368, ECO:0000269|PubMed:15980244, ECO:0000269|PubMed:16496379, ECO:0000269|PubMed:3265470, ECO:0000269|PubMed:3480538}.
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