title: Transposition of three amino acids transforms the human metabotropic glutamate receptor (mGluR)-3-positive allosteric modulation site to mGluR2, and additional characterization of the mGluR2-positive allosteric modulation site.
abstract: Glutamate is a major neurotransmitter in the central nervous system, and abnormal glutamate neurotransmission has been implicated in many neurological disorders, including schizophrenia, Alzheimer's disease, Parkinson's disease, addiction, anxiety, depression, epilepsy, and pain. Metabotropic glutamate receptors (mGluRs) activate intracellular signaling cascades in a G protein-dependent manner, which offer the opportunity for developing drugs that regulate glutamate neurotransmission in a functionally selective manner. In the present study, we further characterize the human mGluR2 (hmGluR2) potentiator binding site by showing that the substitution of the three amino acids found to be required for hmGluR2 potentiation, specifically Ser(688), Gly(689), and Asn(735), with the homologous hmGluR3 amino acids, inactivates the positive allosteric modulator activity of several structurally unique mGluR2 potentiators. Based on the characterization of the hmGluR2 potentiator binding site, we developed a novel scintillation proximity assay that was able to discriminate between compounds that were hmGluR2-specific potentiators, and those that were active on both hmGluR2 and hmGluR3. In addition, we substituted Ser(688), Gly(689), and Asn(735) into hmGluR3 and created an active hmGluR2 allosteric modulation site on the hmGluR3 receptor.
authors.affiliation: Merck Research Laboratories, West Point, Pennsylvania, USA. blake_rowe@merck.com
authors.forename: Blake A
authors.initials: BA
authors.lastname: Rowe
authors.forename: Hervé
authors.initials: H
authors.lastname: Schaffhauser
authors.forename: Sylvia
authors.initials: S
authors.lastname: Morales
authors.forename: Laura S
authors.initials: LS
authors.lastname: Lubbers
authors.forename: Celine
authors.initials: C
authors.lastname: Bonnefous
authors.forename: Theodore M
authors.initials: TM
authors.lastname: Kamenecka
authors.forename: Jeffrey
authors.initials: J
authors.lastname: McQuiston
authors.forename: Lorrie P
authors.initials: LP
authors.lastname: Daggett
mesh_terms: D000494:Allosteric Regulation / Q000235:genetics; D000495:Allosteric Site / Q000235:genetics*; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics; D000596:Amino Acids / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D017354:Point Mutation; D011485:Protein Binding / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D018094:Receptors, Metabotropic Glutamate / Q000737:chemistry* / Q000235:genetics*
chemical_list: D000596:Amino Acids; D018094:Receptors, Metabotropic Glutamate; C108822:metabotropic glutamate receptor 2; C102718:metabotropic glutamate receptor 3