XB-ART-57820
Elife
February 16, 2021;
10
A critical residue in the α1M2-M3 linker regulating mammalian GABAA receptor pore gating by diazepam.
Nors JW
,
Gupta S
,
Goldschen-Ohm MP
.
Abstract
Benzodiazepines (BZDs) are a class of widely prescribed psychotropic drugs that modulate activity of GABAA receptors (GABAARs), neurotransmitter-gated ion channels critical for synaptic transmission. However, the physical basis of this modulation is poorly understood. We explore the role of an important gating domain, the α1M2-M3 linker, in linkage between the BZD site and pore gate. To probe energetics of this coupling without complication from bound agonist, we use a gain of function mutant (α1L9''Tβ2γ2L) directly activated by BZDs. We identify a specific residue whose mutation (α1V279A) more than doubles the energetic contribution of the BZD positive modulator diazepam (DZ) to pore opening and also enhances DZ potentiation of GABA-evoked currents in a wild-type background. In contrast, other linker mutations have little effect on DZ efficiency, but generally impair unliganded pore opening. Our observations reveal an important residue regulating BZD-pore linkage, thereby shedding new light on the molecular mechanism of these drugs.
PubMed ID: 33591271
PMC ID: PMC7899671
Article link: Elife
Grant support: [+]
Department of Neuroscience Startup University of Texas at Austin, STARS University of Texas at Austin
GO keywords: neurotransmitter-gated ion channel clustering
Article Images: [+] show captions
References [+] :
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Chowdhury, Free-energy relationships in ion channels activated by voltage and ligand. 2013, Pubmed
Colquhoun, Binding, gating, affinity and efficacy: the interpretation of structure-activity relationships for agonists and of the effects of mutating receptors. 1999, Pubmed
Connolly, The Cys-loop superfamily of ligand-gated ion channels: the impact of receptor structure on function. 2005, Pubmed
Downing, Benzodiazepine modulation of partial agonist efficacy and spontaneously active GABA(A) receptors supports an allosteric model of modulation. 2006, Pubmed
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Findlay, Allosteric modulation in spontaneously active mutant gamma-aminobutyric acidA receptors. 2001, Pubmed , Xenbase
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Gao, Impaired GABA Neural Circuits Are Critical for Fragile X Syndrome. 2019, Pubmed
Germann, Application of the Co-Agonist Concerted Transition Model to Analysis of GABAA Receptor Properties. 2020, Pubmed
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Goldschen-Ohm, A nonequilibrium binary elements-based kinetic model for benzodiazepine regulation of GABAA receptors. 2015, Pubmed
Gupta, A mechanism for acetylcholine receptor gating based on structure, coupling, phi, and flip. 2017, Pubmed
Hales, An asymmetric contribution to gamma-aminobutyric type A receptor function of a conserved lysine within TM2-3 of alpha1, beta2, and gamma2 subunits. 2006, Pubmed
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Keramidas, The activation mechanism of alpha1beta2gamma2S and alpha3beta3gamma2S GABAA receptors. 2010, Pubmed
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Limon, Loss of functional GABA(A) receptors in the Alzheimer diseased brain. 2012, Pubmed , Xenbase
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Maksay, Thermodynamics of gamma-aminobutyric acid type A receptor binding differentiate agonists from antagonists. 1994, Pubmed
Masiulis, GABA<sub>A</sub> receptor signalling mechanisms revealed by structural pharmacology. 2019, Pubmed
McKernan, Photoaffinity labeling of the benzodiazepine binding site of alpha1beta3gamma2 gamma-aminobutyric acidA receptors with flunitrazepam identifies a subset of ligands that interact directly with His102 of the alpha subunit and predicts orientation of these within the benzodiazepine pharmacophore. 1998, Pubmed
Mellor, Frequency-dependent actions of benzodiazepines on GABAA receptors in cultured murine cerebellar granule cells. 1997, Pubmed
Möhler, A new benzodiazepine pharmacology. 2002, Pubmed
Nayak, Efficiency measures the conversion of agonist binding energy into receptor conformational change. 2020, Pubmed
Nemecz, Emerging Molecular Mechanisms of Signal Transduction in Pentameric Ligand-Gated Ion Channels. 2017, Pubmed
O'Shea, Arg-274 and Leu-277 of the gamma-aminobutyric acid type A receptor alpha 2 subunit define agonist efficacy and potency. 2000, Pubmed
O'Shea, Inverse effects on gating and modulation caused by a mutation in the M2-M3 Linker of the GABA(A) receptor gamma subunit. 2009, Pubmed
Olfson, Benzodiazepine use in the United States. 2015, Pubmed
Olsen, International Union of Pharmacology. LXX. Subtypes of gamma-aminobutyric acid(A) receptors: classification on the basis of subunit composition, pharmacology, and function. Update. 2009, Pubmed
Perrais, Effect of zolpidem on miniature IPSCs and occupancy of postsynaptic GABAA receptors in central synapses. 1999, Pubmed
Pflanz, An intersubunit electrostatic interaction in the GABA<sub>A</sub> receptor facilitates its responses to benzodiazepines. 2019, Pubmed , Xenbase
Phulera, Cryo-EM structure of the benzodiazepine-sensitive α1β1γ2S tri-heteromeric GABA<sub>A</sub> receptor in complex with GABA. 2018, Pubmed
Pless, A tale of ligands big and small: an update on how pentameric ligand-gated ion channels interact with agonists and proteins. 2021, Pubmed
Pritchett, Importance of a novel GABAA receptor subunit for benzodiazepine pharmacology. 1989, Pubmed
Purohit, Functional anatomy of an allosteric protein. 2014, Pubmed
Purohit, Unliganded gating of acetylcholine receptor channels. 2009, Pubmed
Ramamoorthi, The contribution of GABAergic dysfunction to neurodevelopmental disorders. 2011, Pubmed
Rogers, Benzodiazepine and beta-carboline regulation of single GABAA receptor channels of mouse spinal neurones in culture. 1994, Pubmed
Rudolph, GABAA receptor subtypes: Therapeutic potential in Down syndrome, affective disorders, schizophrenia, and autism. 2014, Pubmed
Rüsch, Classic benzodiazepines modulate the open-close equilibrium in alpha1beta2gamma2L gamma-aminobutyric acid type A receptors. 2005, Pubmed , Xenbase
Scheller, Coupled and uncoupled gating and desensitization effects by pore domain mutations in GABA(A) receptors. 2002, Pubmed
Schmitz, Benzodiazepine use, misuse, and abuse: A review. 2020, Pubmed
Sieghart, Subunit composition, distribution and function of GABA(A) receptor subtypes. 2002, Pubmed
Sigel, The Benzodiazepine Binding Sites of GABA<sub>A</sub> Receptors. 2018, Pubmed
Sigel, A closer look at the high affinity benzodiazepine binding site on GABAA receptors. 2011, Pubmed , Xenbase
Sigel, Mapping of the benzodiazepine recognition site on GABA(A) receptors. 2002, Pubmed
Smart, A half century of γ-aminobutyric acid. 2020, Pubmed
Solís-Añez, [Autism, chromosome 15 and the GAbaergic dysfunction hypothesis]. 2008, Pubmed
Steinbach, Applying the Monod-Wyman-Changeux Allosteric Activation Model to Pseudo-Steady-State Responses from GABA<sub>A</sub> Receptors. 2019, Pubmed
Tasneem, Identification of the prokaryotic ligand-gated ion channels and their implications for the mechanisms and origins of animal Cys-loop ion channels. 2005, Pubmed
Venkatachalan, Structural link between γ-aminobutyric acid type A (GABAA) receptor agonist binding site and inner β-sheet governs channel activation and allosteric drug modulation. 2012, Pubmed , Xenbase
Vicini, Actions of benzodiazepine and beta-carboline derivatives on gamma-aminobutyric acid-activated Cl- channels recorded from membrane patches of neonatal rat cortical neurons in culture. 1988, Pubmed
Vien, Compromising the phosphodependent regulation of the GABAAR β3 subunit reproduces the core phenotypes of autism spectrum disorders. 2016, Pubmed
Wagner, Structure and dynamics of the GABA binding pocket: A narrowing cleft that constricts during activation. 2001, Pubmed , Xenbase
Walters, Benzodiazepines act on GABAA receptors via two distinct and separable mechanisms. 2001, Pubmed , Xenbase
Zhu, Structure of a human synaptic GABA<sub>A</sub> receptor. 2018, Pubmed
Akk, GABA Type A Receptor Activation in the Allosteric Coagonist Model Framework: Relationship between EC<sub>50</sub> and Basal Activity. 2019, Pubmed , Xenbase
Bachhuber, Increasing Benzodiazepine Prescriptions and Overdose Mortality in the United States, 1996-2013. 2016, Pubmed
Bode, The impact of human hyperekplexia mutations on glycine receptor structure and function. 2014, Pubmed
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
Braat, The GABAA Receptor as a Therapeutic Target for Neurodevelopmental Disorders. 2015, Pubmed
Campo-Soria, Mechanism of action of benzodiazepines on GABAA receptors. 2006, Pubmed , Xenbase
Chang, Allosteric activation mechanism of the alpha 1 beta 2 gamma 2 gamma-aminobutyric acid type A receptor revealed by mutation of the conserved M2 leucine. 2010, Pubmed , Xenbase
Chowdhury, Free-energy relationships in ion channels activated by voltage and ligand. 2013, Pubmed
Colquhoun, Binding, gating, affinity and efficacy: the interpretation of structure-activity relationships for agonists and of the effects of mutating receptors. 1999, Pubmed
Connolly, The Cys-loop superfamily of ligand-gated ion channels: the impact of receptor structure on function. 2005, Pubmed
Downing, Benzodiazepine modulation of partial agonist efficacy and spontaneously active GABA(A) receptors supports an allosteric model of modulation. 2006, Pubmed
Du, Glycine receptor mechanism elucidated by electron cryo-microscopy. 2016, Pubmed
Findlay, Allosteric modulation in spontaneously active mutant gamma-aminobutyric acidA receptors. 2001, Pubmed , Xenbase
Fluyau, Challenges of the pharmacological management of benzodiazepine withdrawal, dependence, and discontinuation. 2020, Pubmed
Gao, Impaired GABA Neural Circuits Are Critical for Fragile X Syndrome. 2019, Pubmed
Germann, Application of the Co-Agonist Concerted Transition Model to Analysis of GABAA Receptor Properties. 2020, Pubmed
Gibbs, Benzodiazepine receptor photoaffinity labeling: correlation of function with binding. 1985, Pubmed
Gielen, Benzodiazepines modulate GABAA receptors by regulating the preactivation step after GABA binding. 2012, Pubmed , Xenbase
Goldschen-Ohm, An epilepsy-related region in the GABA(A) receptor mediates long-distance effects on GABA and benzodiazepine binding sites. 2010, Pubmed
Goldschen-Ohm, A nonequilibrium binary elements-based kinetic model for benzodiazepine regulation of GABAA receptors. 2015, Pubmed
Gupta, A mechanism for acetylcholine receptor gating based on structure, coupling, phi, and flip. 2017, Pubmed
Hales, An asymmetric contribution to gamma-aminobutyric type A receptor function of a conserved lysine within TM2-3 of alpha1, beta2, and gamma2 subunits. 2006, Pubmed
Hanson, Structural mechanisms underlying benzodiazepine modulation of the GABA(A) receptor. 2008, Pubmed , Xenbase
Hanson, Disulphide trapping of the GABA(A) receptor reveals the importance of the coupling interface in the action of benzodiazepines. 2011, Pubmed , Xenbase
Hernandez, A structural look at GABA<sub>A</sub> receptor mutations linked to epilepsy syndromes. 2020, Pubmed
Im, Interaction of beta-carboline inverse agonists for the benzodiazepine site with another site on GABAA receptors. 1995, Pubmed
Jones, Alcohol involvement in opioid pain reliever and benzodiazepine drug abuse-related emergency department visits and drug-related deaths - United States, 2010. 2014, Pubmed
Jones, Emergency Department Visits and Overdose Deaths From Combined Use of Opioids and Benzodiazepines. 2016, Pubmed
Kash, Coupling of agonist binding to channel gating in the GABA(A) receptor. 2003, Pubmed
Keramidas, The activation mechanism of alpha1beta2gamma2S and alpha3beta3gamma2S GABAA receptors. 2010, Pubmed
Kim, Shared structural mechanisms of general anaesthetics and benzodiazepines. 2020, Pubmed
Kucken, Identification of benzodiazepine binding site residues in the gamma2 subunit of the gamma-aminobutyric acid(A) receptor. 2000, Pubmed
Kumar, Mechanisms of activation and desensitization of full-length glycine receptor in lipid nanodiscs. 2020, Pubmed , Xenbase
Laverty, Cryo-EM structure of the human α1β3γ2 GABA<sub>A</sub> receptor in a lipid bilayer. 2019, Pubmed
Li, The benzodiazepine diazepam potentiates responses of α1β2γ2L γ-aminobutyric acid type A receptors activated by either γ-aminobutyric acid or allosteric agonists. 2013, Pubmed
Limon, Loss of functional GABA(A) receptors in the Alzheimer diseased brain. 2012, Pubmed , Xenbase
Mahdavi, Meta-Analysis of the Association between GABA Receptor Polymorphisms and Autism Spectrum Disorder (ASD). 2019, Pubmed
Maksay, Thermodynamics of gamma-aminobutyric acid type A receptor binding differentiate agonists from antagonists. 1994, Pubmed
Masiulis, GABA<sub>A</sub> receptor signalling mechanisms revealed by structural pharmacology. 2019, Pubmed
McKernan, Photoaffinity labeling of the benzodiazepine binding site of alpha1beta3gamma2 gamma-aminobutyric acidA receptors with flunitrazepam identifies a subset of ligands that interact directly with His102 of the alpha subunit and predicts orientation of these within the benzodiazepine pharmacophore. 1998, Pubmed
Mellor, Frequency-dependent actions of benzodiazepines on GABAA receptors in cultured murine cerebellar granule cells. 1997, Pubmed
Möhler, A new benzodiazepine pharmacology. 2002, Pubmed
Nayak, Efficiency measures the conversion of agonist binding energy into receptor conformational change. 2020, Pubmed
Nemecz, Emerging Molecular Mechanisms of Signal Transduction in Pentameric Ligand-Gated Ion Channels. 2017, Pubmed
O'Shea, Arg-274 and Leu-277 of the gamma-aminobutyric acid type A receptor alpha 2 subunit define agonist efficacy and potency. 2000, Pubmed
O'Shea, Inverse effects on gating and modulation caused by a mutation in the M2-M3 Linker of the GABA(A) receptor gamma subunit. 2009, Pubmed
Olfson, Benzodiazepine use in the United States. 2015, Pubmed
Olsen, International Union of Pharmacology. LXX. Subtypes of gamma-aminobutyric acid(A) receptors: classification on the basis of subunit composition, pharmacology, and function. Update. 2009, Pubmed
Perrais, Effect of zolpidem on miniature IPSCs and occupancy of postsynaptic GABAA receptors in central synapses. 1999, Pubmed
Pflanz, An intersubunit electrostatic interaction in the GABA<sub>A</sub> receptor facilitates its responses to benzodiazepines. 2019, Pubmed , Xenbase
Phulera, Cryo-EM structure of the benzodiazepine-sensitive α1β1γ2S tri-heteromeric GABA<sub>A</sub> receptor in complex with GABA. 2018, Pubmed
Pless, A tale of ligands big and small: an update on how pentameric ligand-gated ion channels interact with agonists and proteins. 2021, Pubmed
Pritchett, Importance of a novel GABAA receptor subunit for benzodiazepine pharmacology. 1989, Pubmed
Purohit, Functional anatomy of an allosteric protein. 2014, Pubmed
Purohit, Unliganded gating of acetylcholine receptor channels. 2009, Pubmed
Ramamoorthi, The contribution of GABAergic dysfunction to neurodevelopmental disorders. 2011, Pubmed
Rogers, Benzodiazepine and beta-carboline regulation of single GABAA receptor channels of mouse spinal neurones in culture. 1994, Pubmed
Rudolph, GABAA receptor subtypes: Therapeutic potential in Down syndrome, affective disorders, schizophrenia, and autism. 2014, Pubmed
Rüsch, Classic benzodiazepines modulate the open-close equilibrium in alpha1beta2gamma2L gamma-aminobutyric acid type A receptors. 2005, Pubmed , Xenbase
Scheller, Coupled and uncoupled gating and desensitization effects by pore domain mutations in GABA(A) receptors. 2002, Pubmed
Schmitz, Benzodiazepine use, misuse, and abuse: A review. 2020, Pubmed
Sieghart, Subunit composition, distribution and function of GABA(A) receptor subtypes. 2002, Pubmed
Sigel, The Benzodiazepine Binding Sites of GABA<sub>A</sub> Receptors. 2018, Pubmed
Sigel, A closer look at the high affinity benzodiazepine binding site on GABAA receptors. 2011, Pubmed , Xenbase
Sigel, Mapping of the benzodiazepine recognition site on GABA(A) receptors. 2002, Pubmed
Smart, A half century of γ-aminobutyric acid. 2020, Pubmed
Solís-Añez, [Autism, chromosome 15 and the GAbaergic dysfunction hypothesis]. 2008, Pubmed
Steinbach, Applying the Monod-Wyman-Changeux Allosteric Activation Model to Pseudo-Steady-State Responses from GABA<sub>A</sub> Receptors. 2019, Pubmed
Tasneem, Identification of the prokaryotic ligand-gated ion channels and their implications for the mechanisms and origins of animal Cys-loop ion channels. 2005, Pubmed
Venkatachalan, Structural link between γ-aminobutyric acid type A (GABAA) receptor agonist binding site and inner β-sheet governs channel activation and allosteric drug modulation. 2012, Pubmed , Xenbase
Vicini, Actions of benzodiazepine and beta-carboline derivatives on gamma-aminobutyric acid-activated Cl- channels recorded from membrane patches of neonatal rat cortical neurons in culture. 1988, Pubmed
Vien, Compromising the phosphodependent regulation of the GABAAR β3 subunit reproduces the core phenotypes of autism spectrum disorders. 2016, Pubmed
Wagner, Structure and dynamics of the GABA binding pocket: A narrowing cleft that constricts during activation. 2001, Pubmed , Xenbase
Walters, Benzodiazepines act on GABAA receptors via two distinct and separable mechanisms. 2001, Pubmed , Xenbase
Zhu, Structure of a human synaptic GABA<sub>A</sub> receptor. 2018, Pubmed