Recombinant Human Large neutral amino acids transporter small subunit 2 (SLC7A8) Protein

Function

Associates with SLC3A2 to form a functional heterodimeric complex that translocates small and large neutral amino acids with broad specificity and a stoichiometry of 1:1. Functions as amino acid antiporter mediating the influx of extracellular essential amino acids mainly in exchange with the efflux of highly concentrated intracellular amino acids (PubMed:10391915, PubMed:11311135, PubMed:11847106, PubMed:12716892, PubMed:15081149, PubMed:15918515, PubMed:29355479, PubMed:33298890, PubMed:34848541). Has relatively symmetrical selectivities but strongly asymmetrical substrate affinities at both the intracellular and extracellular sides of the transporter (PubMed:11847106). This asymmetry allows SLC7A8 to regulate intracellular amino acid pools (mM concentrations) by exchange with external amino acids (uM concentration range), equilibrating the relative concentrations of different amino acids across the plasma membrane instead of mediating their net uptake (PubMed:10391915, PubMed:11847106). May play an essential role in the reabsorption of neutral amino acids from the epithelial cells to the bloodstream in the kidney (PubMed:12716892). 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 (PubMed:12117417). Involved in the cellular activity of small molecular weight nitrosothiols, via the stereoselective transport of L-nitrosocysteine (L-CNSO) across the transmembrane (PubMed:15769744). Imports the thyroid hormone diiodothyronine (T2) and to a smaller extent triiodothyronine (T3) but not rT 3 or thyroxine (T4) (PubMed:26305885). Mediates the uptake of L-DOPA (By similarity). May participate in auditory function (By similarity). Mediates the uptake of leucine and 3-iodo-L-tyrosine (MIT) (PubMed:26305885). Mediates the uptake of 3,5-diiodo-L-tyrosine (DIT) (PubMed:38661522)

Subcellular Location

Cell membrane (Multi-pass membrane protein); Basolateral cell membrane (Multi-pass membrane protein)

Tissue Specificity

Strongest expression is observed in kidney and moderate expression in placenta and brain, followed by liver, prostate, testis, ovary, lymph node, thymus, spleen, skeletal muscle and heart. Also expressed in fetal liver as well as in the retinal pigment epithelial cell line ARPE-19 and the intestinal epithelial cell line Caco-2

Subunit

Disulfide-linked heterodimer composed of the catalytic light chain subunit SLC7A8 and the heavy chain subunit SLC3A2. SLC3A2 acts as chaperones for correct plasma membrane trafficking and stabilization of SLC7A8 and modulates the substrate affinity and specificity of SLC7A8 (PubMed:10391915, PubMed:10574970, PubMed:11311135, PubMed:15769744, PubMed:15918515, PubMed:33066406, PubMed:33298890, PubMed:34848541). ICAM-1 associates with the heterodimer SLC3A2/SLC7A8; this interaction regulates SLC7A8 activity (PubMed:12716892)

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