Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
Different residues in the GABAA receptor benzodiazepine binding pocket mediate benzodiazepine efficacy and binding.
Morlock EV
,
Czajkowski C
.
???displayArticle.abstract???
Benzodiazepines (BZDs) exert their therapeutic actions by binding to the GABA(A) receptor (GABA(A)R) and allosterically modulating GABA-induced chloride currents (I(GABA)). A variety of ligands with divergent structures bind to the BZD site, and the structural mechanisms that couple their binding to potentiation of I(GABA) are not well understood. In this study, we measured the effects of individually mutating 22 residues throughout the BZD binding pocket on the abilities of eszopiclone, zolpidem, and flurazepam to potentiate I(GABA). Wild-type and mutant α(1)β(2)γ(2) GABA(A)Rs were expressed in Xenopus laevis oocytes and analyzed using a two-electrode voltage clamp. GABA EC(50), BZD EC(50), and BZD maximal potentiation were measured. These data, combined with previous radioligand binding data describing the mutations' effects on BZD apparent binding affinities (J Neurosci 28:3490-3499, 2008; J Med Chem 51:7243-7252, 2008), were used to distinguish residues within the BZD pocket that contribute to BZD efficacy and BZD binding. We identified six residues whose mutation altered BZD maximal potentiation of I(GABA) (BZD efficacy) without altering BZD binding apparent affinity, three residues whose mutation altered binding but had no effect on BZD efficacy, and four residues whose mutation affected both binding and efficacy. Moreover, depending on the BZD ligand, the effects of some mutations were different, indicating that the structural mechanisms underlying the ability of BZD ligands with divergent structures to potentiate I(GABA) are distinct.
Amin,
Two tyrosine residues on the alpha subunit are crucial for benzodiazepine binding and allosteric modulation of gamma-aminobutyric acidA receptors.
1997, Pubmed,
Xenbase
Amin,
Two tyrosine residues on the alpha subunit are crucial for benzodiazepine binding and allosteric modulation of gamma-aminobutyric acidA receptors.
1997,
Pubmed
,
Xenbase
Baumann,
Forced subunit assembly in alpha1beta2gamma2 GABAA receptors. Insight into the absolute arrangement.
2002,
Pubmed
,
Xenbase
Benson,
Pharmacology of recombinant gamma-aminobutyric acidA receptors rendered diazepam-insensitive by point-mutated alpha-subunits.
1998,
Pubmed
Berezhnoy,
On the benzodiazepine binding pocket in GABAA receptors.
2004,
Pubmed
,
Xenbase
Boileau,
Identification of transduction elements for benzodiazepine modulation of the GABA(A) receptor: three residues are required for allosteric coupling.
1999,
Pubmed
,
Xenbase
Boileau,
The relative amount of cRNA coding for gamma2 subunits affects stimulation by benzodiazepines in GABA(A) receptors expressed in Xenopus oocytes.
2002,
Pubmed
,
Xenbase
Boileau,
Molecular dissection of benzodiazepine binding and allosteric coupling using chimeric gamma-aminobutyric acidA receptor subunits.
1998,
Pubmed
,
Xenbase
Buhr,
Point mutations of the alpha 1 beta 2 gamma 2 gamma-aminobutyric acid(A) receptor affecting modulation of the channel by ligands of the benzodiazepine binding site.
1996,
Pubmed
,
Xenbase
Buhr,
A point mutation in the gamma2 subunit of gamma-aminobutyric acid type A receptors results in altered benzodiazepine binding site specificity.
1997,
Pubmed
,
Xenbase
Buhr,
Residues at positions 206 and 209 of the alpha1 subunit of gamma-aminobutyric AcidA receptors influence affinities for benzodiazepine binding site ligands.
1997,
Pubmed
,
Xenbase
Campo-Soria,
Mechanism of action of benzodiazepines on GABAA receptors.
2006,
Pubmed
,
Xenbase
Chang,
Stoichiometry of a recombinant GABAA receptor.
1996,
Pubmed
,
Xenbase
Davies,
Characterization of the interaction of zopiclone with gamma-aminobutyric acid type A receptors.
2000,
Pubmed
,
Xenbase
Davies,
Structural requirements for ligand interactions at the benzodiazepine recognition site of the GABA(A) receptor.
1998,
Pubmed
Derry,
Identification of a residue in the gamma-aminobutyric acid type A receptor alpha subunit that differentially affects diazepam-sensitive and -insensitive benzodiazepine site binding.
2004,
Pubmed
Downing,
Benzodiazepine modulation of partial agonist efficacy and spontaneously active GABA(A) receptors supports an allosteric model of modulation.
2005,
Pubmed
Farrar,
Stoichiometry of a ligand-gated ion channel determined by fluorescence energy transfer.
1999,
Pubmed
Ghanouni,
Functionally different agonists induce distinct conformations in the G protein coupling domain of the beta 2 adrenergic receptor.
2001,
Pubmed
Goldschen-Ohm,
An epilepsy-related region in the GABA(A) receptor mediates long-distance effects on GABA and benzodiazepine binding sites.
2010,
Pubmed
Hanson,
Structural mechanisms underlying benzodiazepine modulation of the GABA(A) receptor.
2008,
Pubmed
,
Xenbase
Hanson,
Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
2008,
Pubmed
Kloda,
Agonist-, antagonist-, and benzodiazepine-induced structural changes in the alpha1 Met113-Leu132 region of the GABAA receptor.
2007,
Pubmed
,
Xenbase
Kucken,
Identification of benzodiazepine binding site residues in the gamma2 subunit of the gamma-aminobutyric acid(A) receptor.
2000,
Pubmed
Lavoie,
Direct evidence for diazepam modulation of GABAA receptor microscopic affinity.
1996,
Pubmed
Mellor,
Frequency-dependent actions of benzodiazepines on GABAA receptors in cultured murine cerebellar granule cells.
1997,
Pubmed
Mihic,
A single amino acid of the human gamma-aminobutyric acid type A receptor gamma 2 subunit determines benzodiazepine efficacy.
1994,
Pubmed
,
Xenbase
Möhler,
A new benzodiazepine pharmacology.
2002,
Pubmed
Ortells,
Evolutionary history of the ligand-gated ion-channel superfamily of receptors.
1995,
Pubmed
Rogers,
Benzodiazepine and beta-carboline regulation of single GABAA receptor channels of mouse spinal neurones in culture.
1994,
Pubmed
Rüsch,
Classic benzodiazepines modulate the open-close equilibrium in alpha1beta2gamma2L gamma-aminobutyric acid type A receptors.
2005,
Pubmed
,
Xenbase
Sancar,
Allosteric modulators induce distinct movements at the GABA-binding site interface of the GABA-A receptor.
2011,
Pubmed
,
Xenbase
Schaerer,
Amino acid residue 200 on the alpha1 subunit of GABA(A) receptors affects the interaction with selected benzodiazepine binding site ligands.
1998,
Pubmed
Sieghart,
Subunit composition, distribution and function of GABA(A) receptor subtypes.
2002,
Pubmed
Sigel,
The benzodiazepine binding site of GABAA receptors.
1997,
Pubmed
Swaminath,
Probing the beta2 adrenoceptor binding site with catechol reveals differences in binding and activation by agonists and partial agonists.
2005,
Pubmed
Swaminath,
Sequential binding of agonists to the beta2 adrenoceptor. Kinetic evidence for intermediate conformational states.
2004,
Pubmed
Tan,
Proximity-accelerated chemical coupling reaction in the benzodiazepine-binding site of gamma-aminobutyric acid type A receptors: superposition of different allosteric modulators.
2007,
Pubmed
Tan,
Two neighboring residues of loop A of the alpha1 subunit point towards the benzodiazepine binding site of GABAA receptors.
2007,
Pubmed
Thompson,
Mutation at the putative GABA(A) ion-channel gate reveals changes in allosteric modulation.
1999,
Pubmed
,
Xenbase
Twyman,
Differential regulation of gamma-aminobutyric acid receptor channels by diazepam and phenobarbital.
1989,
Pubmed
Venkatachalan,
Optimized expression vector for ion channel studies in Xenopus oocytes and mammalian cells using alfalfa mosaic virus.
2007,
Pubmed
,
Xenbase
Wieland,
A single histidine in GABAA receptors is essential for benzodiazepine agonist binding.
1992,
Pubmed
Wieland,
Four amino acid exchanges convert a diazepam-insensitive, inverse agonist-preferring GABAA receptor into a diazepam-preferring GABAA receptor.
1994,
Pubmed
Wingrove,
Key amino acids in the gamma subunit of the gamma-aminobutyric acidA receptor that determine ligand binding and modulation at the benzodiazepine site.
1997,
Pubmed
,
Xenbase
