title: Inhibition of the ethanol-induced potentiation of α1 glycine receptor by a small peptide that interferes with Gβγ binding.
abstract: BACKGROUND
  Gβγ interaction with GlyR is an important determinant in ethanol potentiation of this channel.
  
  
  RESULTS
  A small peptide, RQH(C7), can inhibit ethanol potentiation of GlyR currents.
  
  
  CONCLUSIONS
  Results with RQH(C7) indicate that ethanol mediated potentiation of GlyR is in part by Gβγ activation.
  
  
  CONCLUSIONS
  Molecular interaction between Gβγ and GlyR could be used as a target for pharmacological modification of ethanol effects. Previous studies indicate that ethanol can modulate glycine receptors (GlyR), in part, through Gβγ interaction with basic residues in the intracellular loop. In this study, we show that a seven-amino acid peptide (RQH(C7)), which has the primary structure of a motif in the large intracellular loop of GlyR (GlyR-IL), was able to inhibit the ethanol-elicited potentiation of this channel from 47 ± 2 to 16 ± 4%, without interfering with the effect of Gβγ on GIRK (G protein activated inwardly rectifying potassium channel) activation. RQH(C7) displayed a concentration-dependent effect on ethanol action in evoked and synaptic currents. A fragment of GlyR-IL without the basic amino acids did not interact with Gβγ or inhibit ethanol potentiation of GlyR. In silico analysis using docking and molecular dynamics allowed to identify a region of ~350Å(2) involving aspartic acids 186, 228, and 246 in Gβγ where we propose that RQH(C7) binds and exerts its blocking action on the effect of ethanol in GlyR.
authors.affiliation: Department of Physiology, Faculty of Biological Sciences, University of Concepcion, 403901 Concepcion, Chile.
authors.forename: Loreto
authors.initials: L
authors.lastname: San Martin
authors.forename: Fabian
authors.initials: F
authors.lastname: Cerda
authors.forename: Veronica
authors.initials: V
authors.lastname: Jimenez
authors.forename: Jorge
authors.initials: J
authors.lastname: Fuentealba
authors.forename: Braulio
authors.initials: B
authors.lastname: Muñoz
authors.forename: Luis G
authors.initials: LG
authors.lastname: Aguayo
authors.forename: Leonardo
authors.initials: L
authors.lastname: Guzman
mesh_terms: D000431:Ethanol / Q000378:metabolism*; D044387:GTP-Binding Protein beta Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D044388:GTP-Binding Protein gamma Subunits / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D007700:Kinetics; D010455:Peptides / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D018009:Receptors, Glycine / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D044387:GTP-Binding Protein beta Subunits; D044388:GTP-Binding Protein gamma Subunits; D010455:Peptides; D018009:Receptors, Glycine; D000431:Ethanol