title: From transporter to transceptor: signaling from transporters provokes re-evaluation of complex trafficking and regulatory controls: endocytic internalization and intracellular trafficking of nutrient transceptors may, at least in part, be governed by their signaling function.
abstract: When cells are starved of their substrate, many nutrient transporters are induced. These undergo rapid endocytosis and redirection of their intracellular trafficking when their substrate becomes available again. The discovery that some of these transporters also act as receptors, or transceptors, suggests that at least part of the sophisticated controls governing the trafficking of these proteins has to do with their signaling function rather than with control of transport. In yeast, the general amino acid permease Gap1 mediates signaling to the protein kinase A pathway. Its endocytic internalization and intracellular trafficking are subject to amino acid control. Other nutrient transceptors controlling this signal transduction pathway appear to be subject to similar trafficking regulation. Transporters with complex regulatory control have also been suggested to function as transceptors in other organisms. Hence, precise regulation of intracellular trafficking in nutrient transporters may be related to the need for tight control of nutrient-induced signaling.
authors.affiliation: Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, K. U. Leuven, Leuven, Belgium.
authors.forename: Johan
authors.initials: J
authors.lastname: Kriel
authors.forename: Steven
authors.initials: S
authors.lastname: Haesendonckx
authors.forename: Marta
authors.initials: M
authors.lastname: Rubio-Texeira
authors.forename: Griet
authors.initials: G
authors.lastname: Van Zeebroeck
authors.forename: Johan M
authors.initials: JM
authors.lastname: Thevelein
mesh_terms: D026905:Amino Acid Transport Systems / Q000235:genetics / Q000378:metabolism*; D000596:Amino Acids / Q000378:metabolism; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004705:Endocytosis; D015966:Gene Expression Regulation, Fungal; D042541:Intracellular Space / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D011487:Protein Conformation; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D054875:Ubiquitination
chemical_list: D026905:Amino Acid Transport Systems; D000596:Amino Acids; C491145:GAP1 protein, S cerevisiae; D018160:Receptors, Cytoplasmic and Nuclear; D029701:Saccharomyces cerevisiae Proteins; D017868:Cyclic AMP-Dependent Protein Kinases; D009584:Nitrogen