title: Molecular determinants of positive allosteric modulation of the human metabotropic glutamate receptor 2.
abstract: OBJECTIVE
  The activation of the metabotropic glutamate receptor 2 (mGlu2 ) reduces glutamatergic transmission in brain regions where excess excitatory signalling is implicated in disorders such as anxiety and schizophrenia. Positive allosteric modulators (PAMs) can provide a fine-tuned potentiation of these receptors' function and are being investigated as a novel therapeutic approach. An extensive set of mutant human mGlu2 receptors were used to investigate the molecular determinants that are important for positive allosteric modulation at this receptor.
  
  
  METHODS
  Site-directed mutagenesis, binding and functional assays were employed to identify amino acids important for the activity of nine PAMs. The data from the radioligand binding and mutagenesis studies were used with computational docking to predict a binding mode at an mGlu2 receptor model based on the recent structure of the mGlu1 receptor.
  
  
  RESULTS
  New amino acids in TM3 (R635, L639, F643), TM5 (L732) and TM6 (W773, F776) were identified for the first time as playing an important role in the activity of mGlu2 PAMs.
  
  
  CONCLUSIONS
  This extensive study furthers our understanding of positive allosteric modulation of the mGlu2 receptor and can contribute to improved future design of mGlu2 PAMs.
authors.affiliation: Neuroscience Discovery, Janssen Research and Development, Division of Janssen Pharmaceutica, Beerse, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Farinha
authors.forename: H
authors.initials: H
authors.lastname: Lavreysen
authors.forename: L
authors.initials: L
authors.lastname: Peeters
authors.forename: B
authors.initials: B
authors.lastname: Russo
authors.forename: S
authors.initials: S
authors.lastname: Masure
authors.forename: A A
authors.initials: AA
authors.lastname: Trabanco
authors.forename: J
authors.initials: J
authors.lastname: Cid
authors.forename: G
authors.initials: G
authors.lastname: Tresadern
mesh_terms: D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D016466:CHO Cells; D003412:Cricetulus; D004305:Dose-Response Relationship, Drug; D015195:Drug Design; D018683:Excitatory Amino Acid Agents / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D018698:Glutamic Acid / Q000378:metabolism; D006801:Humans; D008024:Ligands; D062105:Molecular Docking Simulation; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D011485:Protein Binding; D011487:Protein Conformation; D018094:Receptors, Metabotropic Glutamate / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D013329:Structure-Activity Relationship; D014162:Transfection
chemical_list: D018683:Excitatory Amino Acid Agents; D008024:Ligands; D018094:Receptors, Metabotropic Glutamate; C108822:metabotropic glutamate receptor 2; D018698:Glutamic Acid