Sodium-Dependent Homo- and Hetero-Exchange of Neutral Amino Acids Mediated by the Amino Acid Transporter ATB°

1998 ◽  
Vol 245 (3) ◽  
pp. 824-829 ◽  
Author(s):  
Viviana Torres-Zamorano ◽  
Frederick H. Leibach ◽  
Vadivel Ganapathy
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Transporter ◽  
Neutral Amino Acids ◽  
Sodium Dependent ◽  
Acid Transporter

scholarly journals The zebrafish cationic amino acid transporter/glycoprotein-associated family: sequence and spatiotemporal distribution during development of the transport system b0,+ (slc3a1/slc7a9)

2021 ◽  
Author(s):  
Ståle Ellingsen ◽  
Shailesh Narawane ◽  
Anders Fjose ◽  
Tiziano Verri ◽  
Ivar Rønnestad
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Transport System ◽  
Expression Patterns ◽  
Amino Acid Transporter ◽  
Rapid Screening ◽  
Cationic Amino Acid ◽  
Large Neutral Amino Acids ◽  
Neutral Amino Acids ◽  
Acid Transporter

AbstractSystem b0,+ absorbs lysine, arginine, ornithine, and cystine, as well as some (large) neutral amino acids in the mammalian kidney and intestine. It is a heteromeric amino acid transporter made of the heavy subunit SLC3A1/rBAT and the light subunit SLC7A9/b0,+AT. Mutations in these two genes can cause cystinuria in mammals. To extend information on this transport system to teleost fish, we focused on the slc3a1 and slc7a9 genes by performing comparative and phylogenetic sequence analysis, investigating gene conservation during evolution (synteny), and defining early expression patterns during zebrafish (Danio rerio) development. Notably, we found that slc3a1 and slc7a9 are non-duplicated in the zebrafish genome. Whole-mount in situ hybridization detected co-localized expression of slc3a1 and slc7a9 in pronephric ducts at 24 h post-fertilization and in the proximal convoluted tubule at 3 days post-fertilization (dpf). Notably, both the genes showed co-localized expression in epithelial cells in the gut primordium at 3 dpf and in the intestine at 5 dpf (onset of exogenous feeding). Taken together, these results highlight the value of slc3a1 and slc7a9 as markers of zebrafish kidney and intestine development and show promise for establishing new zebrafish tools that can aid in the rapid screening(s) of substrates. Importantly, such studies will help clarify the complex interplay between the absorption of dibasic amino acids, cystine, and (large) neutral amino acids and the effect(s) of such nutrients on organismal growth.

Reabsorption of neutral amino acids mediated by amino acid transporter LAT2 and TAT1 in the basolateral membrane of proximal tubule

2005 ◽  
Vol 28 (4) ◽  
pp. 421-432 ◽  
Author(s):  
Sun Young Park ◽  
Jong-Keun Kim ◽  
In Jin Kim ◽  
Bong Kyu Choi ◽  
Kyu Yong Jung ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Proximal Tubule ◽  
Basolateral Membrane ◽  
Amino Acid Transporter ◽  
Neutral Amino Acids ◽  
Acid Transporter

scholarly journals Transport of Methylmercury through the Epithelial Type Amino Acid Transporter System B0

2019 ◽  
Vol 5 (2) ◽  
pp. 127-136
Author(s):  
Rafiqul Islam ◽  
Naohiko Anzai ◽  
Nesar Ahmed ◽  
Mohammad Ahtashamul Haque ◽  
Shamima Ferdous ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Molecular Mechanism ◽  
Xenopus Oocytes ◽  
Critical Role ◽  
Amino Acid Transporter ◽  
Intestinal Lumen ◽  
Dependent Manner ◽  
Sodium Dependent ◽  
Acid Transporter

Background: System B0 is a sodium dependent transporter that transports wide variety of neutral amino acids in the intestinal and renal proximal tubular epithelial cells. Methylmercury (MeHg) readily and non-enzymatically reacts with cysteine to form conjugate structurally similar to the amino acid methionine. Objective: In this study, we investigated the molecular mechanism of absorptive transport of MeHg in intestine using Xenopus oocytes expressing hB0AT1 and the uptake of metylmercry-Cys (MeHg-Cys) by heterodimeric amino acids transporter. Methodology: We confirmed the uptake of [14C] L-Leucine a potent substrate for the hB0AT1 amino acids transporter. The uptake of [14C] L-leucine by hB0AT1 was inhibited by MeHg-Cys conjugate, leucine, cysteine, methinine and phenylalanine in concentration–dependent manner. The IC50 of MeHg-Cys conjugate was significantly lower than that of leucine, cysteine, methinine and phenylalanine, indicating that hB0AT1 is a high affinity MeHg transporter. To assess MeHg-Cys conjugate transport, we measured [14C] MeHg uptake in Xenopus oocytes expressing hB0AT1 in presence or absence of sodium. The [14C] MeHg was transport only in the presence of cysteine and the transport was significantly sodium dependent and inhibited by a system B0 inhibitor 2-aminobicyclo-[2,21]- haptane-2-carboxylic acid (BCH). Result: The current findings indicate that hB0AT1 and heterodimeric amino acids absorb MeHg in the form of cysteine conjugate from the intestinal lumen across the brush-border membrane in to the cells and is supposed to be plays a critical role in the pathogenesis of Minamata disease and present results descried a major molecular mechanism by which MeHg is transported across cell membranes and indicate that metal complexes may form a novel class of substrates for amino acid carriers. Conclusion: In this experiment the results also suggest that uptake of Methionine and MeHg-Cys by heterodimeric amino acid transporter is significantly correlated where the uptake of Methionine and MeHg-Cys between heterodimeric amino acid transporter and hB0AT1 is not correlated. Journal of National Institute of Neurosciences Bangladesh, 2019;5(2): 127-136

scholarly journals Neutral amino acid transporter ASCT2 displays substrate-induced Na+ exchange and a substrate-gated anion conductance

2000 ◽  
Vol 346 (3) ◽  
pp. 705-710 ◽  
Author(s):  
Angelika BRÖER ◽  
Carsten WAGNER ◽  
Florian LANG ◽  
Stefan BRÖER
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Anion Channel ◽  
Amino Acid Transporter ◽  
Neutral Amino Acid ◽  
Xenopus Laevis Oocytes ◽  
Anion Conductance ◽  
Neutral Amino Acid Transporter ◽  
Inward Currents ◽  
Acid Transporter

The neutral amino acid transporter ASCT2 mediates electroneutral obligatory antiport but at the same time requires Na+ for its function. To elucidate the mechanism, ASCT2 was expressed in Xenopus laevis oocytes and transport was analysed by flux studies and two-electrode voltage clamp recordings. Flux studies with 22NaCl indicated that the uptake of one molecule of glutamine or alanine is accompanied by the uptake of four to seven Na+ ions. Similarly to the transport of amino acids, the Na+ uptake was mediated by an obligatory Na+ exchange mechanism that depended on the presence of amino acids but was not stoichiometrically coupled to the amino acid transport. Other cations could not replace Na+ in this transport mechanism. When NaCl was replaced by NaSCN in the transport buffer, the superfusion of oocytes with amino acid substrates resulted in large inward currents, indicating the presence of a substrate-gated anion channel in the ASCT2 transporter. The Km for glutamine derived from these experiments is in good agreement with the Km derived from flux studies; it varied between 40 and 90 μM at holding potentials of -60 and -20 mV respectively. The permeability of the substrate-gated anion conductance decreased in the order SCN- NO3- > I- > Cl- and also required the presence of Na+.

scholarly journals Intestinal peptidases form functional complexes with the neutral amino acid transporter B0AT1

2012 ◽  
Vol 446 (1) ◽  
pp. 135-148 ◽  
Author(s):  
Stephen J. Fairweather ◽  
Angelika Bröer ◽  
Megan L. O'Mara ◽  
Stefan Bröer
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Amino Acid Transporter ◽  
The Body ◽  
Site Directed Mutagenesis ◽  
Substrate Affinity ◽  
Xenopus Laevis Oocytes ◽  
Acid Transporter

The brush-border membrane of the small intestine and kidney proximal tubule are the major sites for the absorption and re-absorption of nutrients in the body respectively. Transport of amino acids is mediated through the action of numerous secondary active transporters. In the mouse, neutral amino acids are transported by B0AT1 [broad neutral (0) amino acid transporter 1; SLC6A19 (solute carrier family 6 member 19)] in the intestine and by B0AT1 and B0AT3 (SLC6A18) in the kidney. Immunoprecipitation and Blue native electrophoresis of intestinal brush-border membrane proteins revealed that B0AT1 forms complexes with two peptidases, APN (aminopeptidase N/CD13) and ACE2 (angiotensin-converting enzyme 2). Physiological characterization of B0AT1 expressed together with these peptidases in Xenopus laevis oocytes revealed that APN increased the substrate affinity of the transporter up to 2.5-fold and also increased its surface expression (Vmax). Peptide competition experiments, in silico modelling and site-directed mutagenesis of APN suggest that the catalytic site of the peptidase is involved in the observed changes of B0AT1 apparent substrate affinity, possibly by increasing the local substrate concentration. These results provide evidence for the existence of B0AT1-containing digestive complexes in the brush-border membrane, interacting differentially with various peptidases, and responding to the dynamic needs of nutrient absorption in the intestine and kidney.

scholarly journals Size does matter: 18 amino acids at the N-terminal tip of an amino acid transporter in Leishmania determine substrate specificity

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Doreen Schlisselberg ◽  
Eldar Mazarib ◽  
Ehud Inbar ◽  
Doris Rentsch ◽  
Peter J. Myler ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Substrate Specificity ◽  
Amino Acid Transporter ◽  
Acid Transporter

scholarly journals Microarray analysis reveals the inhibition of intestinal expression of nutrient transporters in piglets infected with porcine epidemic diarrhea virus

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Junmei Zhang ◽  
Di Zhao ◽  
Dan Yi ◽  
Mengjun Wu ◽  
Hongbo Chen ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Transporter ◽  
Nutrient Transporters ◽  
Solute Carrier Family ◽  
Diarrhea Virus ◽  
Expression Of Genes ◽  
Sodium Dependent ◽  
Solute Carrier ◽  
Porcine Epidemic Diarrhea ◽  
Acid Transporter

AbstractPorcine epidemic diarrhea virus (PEDV) infection can induce intestinal dysfunction, resulting in severe diarrhea and even death, but the mode of action underlying these viral effects remains unclear. This study determined the effects of PEDV infection on intestinal absorption and the expression of genes for nutrient transporters via biochemical tests and microarray analysis. Sixteen 7-day-old healthy piglets fed a milk replacer were randomly allocated to one of two groups. After 5-day adaption, piglets (n = 8/group) were orally administrated with either sterile saline or PEDV (the strain from Yunnan province) at 104.5 TCID50 (50% tissue culture infectious dose) per pig. All pigs were orally infused D-xylose (0.1 g/kg BW) on day 5 post PEDV or saline administration. One hour later, jugular vein blood samples as well as intestinal samples were collected for further analysis. In comparison with the control group, PEDV infection increased diarrhea incidence, blood diamine oxidase activity, and iFABP level, while reducing growth and plasma D-xylose concentration in piglets. Moreover, PEDV infection altered plasma and jejunal amino acid profiles, and decreased the expression of aquaporins and amino acid transporters (L-type amino acid transporter 1, sodium-independent amino acid transporter, B(°,+)-type amino acid transport protein, sodium-dependent neutral amino acid transporter 1, sodium-dependent glutamate/aspartate transporter 3, and peptide transporter (1), lipid transport and metabolism-related genes (lipoprotein lipase, apolipoprotein A1, apolipoprotein A4, apolipoprotein C2, solute carrier family 27 member 2, solute carrier family 27 member 4, fatty acid synthase, and long-chain acyl-CoA synthetase (3), and glucose transport genes (glucose transporter-2 and insulin receptor) in the jejunum. However, PEDV administration increased mRNA levels for phosphoenolpyruvate carboxykinase 1, argininosuccinate synthase 1, sodium/glucose co-transporter-1, and cystic fibrosis transmembrane conductance regulator in the jejunum. Collectively, these comprehensive results indicate that PEDV infection induces intestinal injury and inhibits the expression of genes encoding for nutrient transporters.

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