title: Up-Regulation of the Excitatory Amino Acid Transporters EAAT1 and EAAT2 by Mammalian Target of Rapamycin.
abstract: BACKGROUND
  The excitatory amino-acid transporters EAAT1 and EAAT2 clear glutamate from the synaptic cleft and thus terminate neuronal excitation. The carriers are subject to regulation by various kinases. The EAAT3 isoform is regulated by mammalian target of rapamycin (mTOR). The present study thus explored whether mTOR influences transport by EAAT1 and/or EAAT2.
  
  
  METHODS
  cRNA encoding wild type EAAT1 (SLC1A3) or EAAT2 (SLC1A2) was injected into Xenopus oocytes without or with additional injection of cRNA encoding mTOR. Dual electrode voltage clamp was performed in order to determine electrogenic glutamate transport (IEAAT). EAAT2 protein abundance was determined utilizing chemiluminescence.
  
  
  RESULTS
  Appreciable IEAAT was observed in EAAT1 or EAAT2 expressing but not in water injected oocytes. IEAAT was significantly increased by coexpression of mTOR. Coexpression of mTOR increased significantly the maximal IEAAT in EAAT1 or EAAT2 expressing oocytes, without significantly modifying affinity of the carriers. Moreover, coexpression of mTOR increased significantly EAAT2 protein abundance in the cell membrane.
  
  
  CONCLUSIONS
  The kinase mTOR up-regulates the excitatory amino acid transporters EAAT1 and EAAT2.
authors.affiliation: Department of Cardiology, Vascular Medicine and Physiology I, University of Tuebingen, Tuebingen, Germany.
authors.forename: Abeer
authors.initials: A
authors.lastname: Abousaab
authors.forename: Nestor Luis
authors.initials: NL
authors.lastname: Uzcategui
authors.forename: Bhaeldin
authors.initials: B
authors.lastname: Elsir
authors.forename: Florian
authors.initials: F
authors.lastname: Lang
mesh_terms: D000818:Animals; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D027341:Excitatory Amino Acid Transporter 1 / Q000378:metabolism*; D027342:Excitatory Amino Acid Transporter 2 / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism; D009865:Oocytes; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism*; D015854:Up-Regulation; D014982:Xenopus laevis
chemical_list: D027341:Excitatory Amino Acid Transporter 1; D027342:Excitatory Amino Acid Transporter 2; D018698:Glutamic Acid; D058570:TOR Serine-Threonine Kinases