title: The role of amino acid transporters in nutrition.
abstract: OBJECTIVE
  We consider recent advances in epithelial amino acid transport physiology and our understanding of the functioning of amino acid transporters as sensors, as well as carriers, of tissue nutrient supplies.
  
  
  RESULTS
  Gut hormones (e.g. leptin) may regulate intestinal amino acid transporter activity by a variety of mechanisms, although the overall functional significance of such regulation is not yet fully understood. Important functional interactions between amino acid transporters and nutrient-signalling pathways which regulate metabolism [e.g. the mammalian target of rapamycin (mTOR)C1 pathway which promotes cell growth] have been revealed in recent studies. Amino acid transporters on endosomal (e.g. lysosomal) membranes may be of unexpected significance as intracellular nutrient sensors. It is also now evident that certain amino acid transporters may have dual receptor-transporter functions and act as 'transceptors' to sense amino acid availability upstream of signal pathways.
  
  
  CONCLUSIONS
  Increased knowledge on the timescale of the amino acid sensor-signal-effector process(es) should help in the optimization of protein-feeding regimes to gain maximum anabolic effect. New opportunities for nutritional therapy include targeting of amino acid transceptors to promote protein-anabolic signals and mechanisms up-regulating amino acid transporter expression to improve absorptive capacity for nutrients.
authors.affiliation: Division of Cell Signalling & Immunology, College of Life Sciences, University of Dundee, Sir James Black Centre, Dundee, UK.
authors.forename: Nadège
authors.initials: N
authors.lastname: Poncet
authors.forename: Peter M
authors.initials: PM
authors.lastname: Taylor
mesh_terms: D000042:Absorption; D027182:Amino Acid Transport System y+ / Q000235:genetics / Q000378:metabolism; D027241:Amino Acid Transport System y+L; D026905:Amino Acid Transport Systems / Q000378:metabolism*; D000596:Amino Acids / Q000493:pharmacokinetics; D000818:Animals; D005502:Food; D005768:Gastrointestinal Hormones / Q000378:metabolism; D000076222:Mechanistic Target of Rapamycin Complex 1; D051379:Mice; D046912:Multiprotein Complexes; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D058570:TOR Serine-Threonine Kinases; D015854:Up-Regulation
chemical_list: D027182:Amino Acid Transport System y+; D027241:Amino Acid Transport System y+L; D026905:Amino Acid Transport Systems; D000596:Amino Acids; D005768:Gastrointestinal Hormones; D046912:Multiprotein Complexes; D011506:Proteins; C518287:Slc7a7 protein, mouse; D000076222:Mechanistic Target of Rapamycin Complex 1; D058570:TOR Serine-Threonine Kinases