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Pflugers Arch
2007 Jun 01;4543:507-16. doi: 10.1007/s00424-007-0209-3.
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Recycling of aromatic amino acids via TAT1 allows efflux of neutral amino acids via LAT2-4F2hc exchanger.
Ramadan T
,
Camargo SM
,
Herzog B
,
Bordin M
,
Pos KM
,
Verrey F
.
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The rate of amino acid efflux from individual cells needs to be adapted to cellular demands and plays a central role for the control of extracellular amino acid homeostasis. A particular example of such an outward amino acid transport is the basolateral efflux from transporting epithelial cells located in the small intestine and kidneyproximal tubule. Because LAT2-4F2hc (Slc7a8-Slc3a2), the best known basolateral neutral amino acid transporter of these epithelial cells, functions as an obligatory exchanger, we tested whether TAT1 (Slc16a10), the aromatic amino-acid facilitated diffusion transporter, might allow amino acid efflux via this exchanger by recycling its influx substrates. In this study, we show by immunofluorescence that TAT1 and LAT2 indeed colocalize in the early kidneyproximal tubule. Using the Xenopus laevis oocytes expression system, we show that L-glutamine is released from oocytes into an amino-acid-free medium only when both transporters are coexpressed. High-performance liquid chromatography analysis reveals that several other neutral amino acids are released as well. The transport function of both TAT1 and LAT2-4F2hc is necessary for this efflux, as coexpression of functionally inactive but surface-expressed mutants is ineffective. Based on negative results of coimmunoprecipitation and crosslinking experiments, the physical interaction of these transporters does not appear to be required. Furthermore, replacement of TAT1 or LAT2-4F2hc by the facilitated diffusion transporter LAT4 or the obligatory exchanger LAT1, respectively, supports similar functional cooperation. Taken together, the results suggest that the aromatic amino acid diffusion pathway TAT1 can control neutral amino acid efflux via neighboring exchanger LAT2-4F2hc, by recycling its aromatic influx substrates.
Barriere,
Molecular basis of oligoubiquitin-dependent internalization of membrane proteins in Mammalian cells.
2006, Pubmed
Barriere,
Molecular basis of oligoubiquitin-dependent internalization of membrane proteins in Mammalian cells.
2006,
Pubmed
Bauch,
Functional cooperation of epithelial heteromeric amino acid transporters expressed in madin-darby canine kidney cells.
2003,
Pubmed
Bodoy,
Identification of LAT4, a novel amino acid transporter with system L activity.
2005,
Pubmed
,
Xenbase
Bröer,
Molecular cloning of mouse amino acid transport system B0, a neutral amino acid transporter related to Hartnup disorder.
2004,
Pubmed
Camargo,
Steady-state kinetic characterization of the mouse B(0)AT1 sodium-dependent neutral amino acid transporter.
2005,
Pubmed
,
Xenbase
Chen,
Epithelial sodium channel regulated by aldosterone-induced protein sgk.
1999,
Pubmed
,
Xenbase
Cynober,
Plasma amino acid levels with a note on membrane transport: characteristics, regulation, and metabolic significance.
2002,
Pubmed
Fernández,
Basolateral LAT-2 has a major role in the transepithelial flux of L-cystine in the renal proximal tubule cell line OK.
2003,
Pubmed
Filho,
Simultaneous measurements of free amino acid patterns of plasma, muscle and erythrocytes in healthy human subjects.
1997,
Pubmed
Fischer,
Targeted mutations in the psaC gene of Chlamydomonas reinhardtii: preferential reduction of FB at low temperature is not accompanied by altered electron flow from photosystem I to ferredoxin.
1997,
Pubmed
Furriols,
rBAT, related to L-cysteine transport, is localized to the microvilli of proximal straight tubules, and its expression is regulated in kidney by development.
1993,
Pubmed
,
Xenbase
Hill,
Isolation and characterization of the Xenopus oocyte plasma membrane: a new method for studying activity of water and solute transporters.
2005,
Pubmed
,
Xenbase
Kim,
Expression cloning of a Na+-independent aromatic amino acid transporter with structural similarity to H+/monocarboxylate transporters.
2001,
Pubmed
,
Xenbase
Kim,
The human T-type amino acid transporter-1: characterization, gene organization, and chromosomal location.
2002,
Pubmed
,
Xenbase
Kleta,
Mutations in SLC6A19, encoding B0AT1, cause Hartnup disorder.
2004,
Pubmed
Medintz,
A PEST-like sequence in the N-terminal cytoplasmic domain of Saccharomyces maltose permease is required for glucose-induced proteolysis and rapid inactivation of transport activity.
2000,
Pubmed
Meier,
Activation of system L heterodimeric amino acid exchangers by intracellular substrates.
2002,
Pubmed
,
Xenbase
Palacín,
The genetics of heteromeric amino acid transporters.
2005,
Pubmed
Pfeiffer,
Luminal heterodimeric amino acid transporter defective in cystinuria.
1999,
Pubmed
,
Xenbase
Pfeiffer,
Amino acid transport of y+L-type by heterodimers of 4F2hc/CD98 and members of the glycoprotein-associated amino acid transporter family.
1999,
Pubmed
,
Xenbase
Pohl,
The size of the unstirred layer as a function of the solute diffusion coefficient.
1998,
Pubmed
Ramadan,
Basolateral aromatic amino acid transporter TAT1 (Slc16a10) functions as an efflux pathway.
2006,
Pubmed
,
Xenbase
Rechsteiner,
PEST sequences and regulation by proteolysis.
1996,
Pubmed
Rossier,
LAT2, a new basolateral 4F2hc/CD98-associated amino acid transporter of kidney and intestine.
1999,
Pubmed
,
Xenbase
Takada,
Rapid steady-state analysis of blood-brain transfer of L-Trp in rat, with special reference to the plasma protein binding.
1993,
Pubmed
Taylor,
Amino-acid-dependent modulation of amino acid transport in Xenopus laevis oocytes.
1996,
Pubmed
,
Xenbase
Verrey,
Novel renal amino acid transporters.
2005,
Pubmed
Verrey,
System L: heteromeric exchangers of large, neutral amino acids involved in directional transport.
2003,
Pubmed
Wagner,
Regulation of the expression of the Cl-/anion exchanger pendrin in mouse kidney by acid-base status.
2002,
Pubmed
