Mutations of γ-aminobutyric acid and glycine receptors change alcohol cutoff: Evidence for an alcohol receptor?

Wick, Marilee J.; Mihic, S. John; Ueno, S.; Mascia, Maria Paola; Trudell, James R.; Brozowski, Susan J.; Ye, Qing; Harrison, Neil L.; Harris, R. Adron

doi:10.1073/pnas.95.11.6504

Cited by 209 publications

(219 citation statements)

References 27 publications

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“…Other investigators have presented evidence that alcohols and anesthetics are able to bind to a site formed by residues in the M2 and M3 domains of GABA A and glycine receptors and regulate channel function in a manner that is dependent upon volume occupation of the site (18,20,30,31). In this study, we did not initially observe a relation between ethanol sensitivity and molecular volume of the substitution at NR2A(Met 823 ).…”

Section: Discussioncontrasting

confidence: 39%

A Site of Alcohol Action in the Fourth Membrane-associated Domain of the N-Methyl-D-aspartate Receptor

Ren

Honse

Peoples

2003

Journal of Biological Chemistry

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The N-methyl-D-aspartate (NMDA) subtype of ionotropic glutamate receptor is an important mediator of the behavioral effects of ethanol in the central nervous system. Although ethanol is known to inhibit NMDA receptors by influencing ion-channel gating, its molecular site of action and the mechanism underlying this effect have not been established. We have previously identified a conserved methionine residue in the fourth membrane-associated domain of the NMDA receptor NR2A subunit (Met 823 ) that influences desensitization and gating of the ion channel. Here we report that this residue plays an important role in mediating the effect of ethanol on the NMDA receptor. Ethanol IC 50 values among functional substitution mutants at this position varied over the range ϳ130 -225 mM. There was a weak correlation between ethanol IC 50 and mean open time of NR2A(Met 823 ) mutants that was dependent on inclusion of the value for the tryptophan mutant. In the absence of this value, there was no trend toward a correlation among the remaining mutants. Desensitization appeared to influence the action of ethanol, because ethanol IC 50 of the mutants was correlated with the steadystate to peak current ratio. With the exception of tryptophan, ethanol sensitivity was significantly related to the molecular volume and hydrophobicity of the substituent. The relation between ethanol sensitivity and the molecular volume and hydrophobicity at this position suggests that this residue interacts with or forms part of a site of ethanol action and that the presence of a tryptophan residue in this site disrupts its ability to interact with ethanol.Ethyl alcohol or ethanol, one of the oldest and most widely abused drugs, produces a well known spectrum of behavioral effects primarily through actions on ion channels in the nervous system. The N-methyl-D-aspartate (NMDA) 1 receptor, a subtype of receptor for the major excitatory neurotransmitter glutamate, is thought to be of particular importance in mediating the effects of alcohols in the mammalian brain. Ethanol inhibits NMDA-activated current in central neurons (1, 2) as well as NMDA-evoked Ca 2ϩ flux, cyclic GMP production, and neurotransmitter release (3-6). Studies using in vivo electrophysiological techniques have also reported ethanol inhibition of NMDA receptors at relevant concentrations (7). Ethanol appears to interact with a novel allosteric site, which is independent of the recognition site for the agonist glutamate or coagonist glycine (6, 8 -12), and reduces the mean open time and opening frequency of the channel (13,14).Presumed alcohol binding sites have been identified on a small number of receptors and ion channels, but the location and nature of these sites vary considerably. Sites of alcohol interaction have been reported to be located in the ion-channel lumen of nicotinic acetylcholine receptors from muscle (15) in a cytoplasmic loop of a Drosophila potassium channel (16), in the cytoplasmic C terminus of G-protein-coupled inwardly rectifying potassium channels (17), and in ...

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Section: Discussioncontrasting

confidence: 39%

A Site of Alcohol Action in the Fourth Membrane-associated Domain of the N-Methyl-D-aspartate Receptor

Ren

Honse

Peoples

2003

Journal of Biological Chemistry

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“…Molecular modeling studies of alcohol-binding sites in the GABA A and glycine receptors have identified a potential site as a hydrophobic pocket formed by amino acids from the second and third transmembrane domains 6,9,[35][36][37] . The recent structure of the transmembrane domains of the Torpedo n-acetylcholine receptor (nAchR) supports this model 38 and suggests the alcohol-binding site is in a pocket between the transmembrane helices.…”

Section: Towards a "High-affinity" Alcohol Binding Sitementioning

confidence: 99%

“…4 and 5). Single point mutations in these sites can abolish or dramatically reduce the sensitivity to ethanol [6][7][8] or can change the length of the alcohol that affects receptor function 9 . It is proposed that alcohols stabilize a conformation of the receptor with altered function that persists until the alcohol is removed (reviewed in refs.…”

Section: Introductionmentioning

confidence: 99%

Structure of a specific alcohol-binding site defined by the odorant binding protein LUSH from Drosophila melanogaster

Kruse

Zhao

Smith

et al. 2003

Nat Struct Mol Biol

213

265

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SummaryWe have solved the high-resolution crystal structure of the Drosophila melanogaster alcoholbinding protein LUSH in the complexes it forms with a series of short chain n-alcohols. LUSH is the first known non-enzyme protein with a defined in vivo alcohol-binding function. The structure of LUSH reveals a set of molecular interactions that define a specific alcohol-binding site. A group of amino acids, Thr57, Ser52 and Thr48 form a network of concerted hydrogen bonds between the protein and the alcohol that provide a structural motif to increase alcohol binding affinity at this site. This motif appears to be conserved in a number of mammalian ligand-gated ion channels that are directly implicated in the pharmacological effects of alcohol. Further, these sequences are found in regions of ion-channels that are known to infer alcohol sensitivity. We suggest the alcohol-binding site in LUSH represents a general model for alcohol-binding sites in proteins.

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“…Position 15′ of the 5-HT 3A receptors TM2 domain is a non-pore-facing amino acid residue (Reeves et al, 2001;Panicker et al, 2002). In addition to its role in channel gating, the amino acid residue at 15′ also appears to have important roles in channel modulation by alcohol and anesthetics (Mihic et al, 1997;Wick et al, 1998), and binding of these drugs to a hydrophobic pocket involving this residue alters receptor function. In a separate study, we have demonstrated that L293 is critical for alcohol actions on the 5-HT 3A receptor; and L293C and L293S mutations abolish alcohol modulation (Hu et al, 2006).…”

Section: Discussionmentioning

confidence: 99%

“…2A. Residue L293 is in the same 15′ position as a residue in the GABA A receptor that has important roles in channel gating (Findlay et al, 2001;Scheller & Forman, 2002) and modulation by alcohols and general anesthetics (Mihic et al, 1997;Wick et al, 1998). This amino acid residue is thought to reside on the non-porefacing side of TM2 domain (Panicker et al, 2002;Reeves et al, 2001).…”

Section: Role Of L293 In the Modulatory Action Of 5-himentioning

confidence: 99%

The L293 residue in transmembrane domain 2 of the 5-HT3A receptor is a molecular determinant of allosteric modulation by 5-hydroxyindole

Lovinger

2008

Neuropharmacology

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Allosteric modulation of ligand-gated ion channels can play important roles in shaping synaptic transmission. The function of the 5-hydroxytryptamine (serotonin) type 3 (5-HT 3 ) receptor, a member of the Cys-loop ligand-gated ion channel superfamily, is modulated by a variety of compounds such as alcohols, anesthetics and 5-hydroxyindole (5-HI). In the present study, the molecular determinants of allosteric modulation by 5-HI were explored in N1E-115 neuroblastoma cells expressing the native 5-HT 3 receptor and HEK 293 cells transfected with the recombinant 5-HT 3A receptor using molecular biology and whole-cell patch-clamp techniques. 5-HI potentiated 5-HT-activated currents in both N1E-115 cells and HEK 293 cells, and significantly decreased current desensitization and deactivation. Substitution of Leu293 (L293, L15′) in the second transmembrane domain (TM2) with cysteine (L293C) or serine (L293S) abolished 5-HI modulation. Other mutations in the TM2 domain, such as D298A and T284F, failed to alter 5-HI modulation. The L293S mutation enhanced dopamine efficacy and converted 5-HI into a partial agonist at the mutant receptor. These data suggest that 5-HI stabilizes the 5-HT 3A receptor in the open state by decreasing both desensitization and 5-HT unbinding/channel closing; and L293 is a common site for both channel gating and allosteric modulation by 5-HI. Our observations also indicate existence of a second 5-HI recognition site on the 5-HT 3A receptor which may overlap with the 5-HT binding site and is not involved in the positive modulation by 5-HI. These findings support the idea that there are two discrete sites for 5-HI allosteric modulation and direct activation in the 5-HT 3A receptor.

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Mutations of γ-aminobutyric acid and glycine receptors change alcohol cutoff: Evidence for an alcohol receptor?

Cited by 209 publications

References 27 publications

A Site of Alcohol Action in the Fourth Membrane-associated Domain of the N-Methyl-D-aspartate Receptor

A Site of Alcohol Action in the Fourth Membrane-associated Domain of the N-Methyl-D-aspartate Receptor

Structure of a specific alcohol-binding site defined by the odorant binding protein LUSH from Drosophila melanogaster

The L293 residue in transmembrane domain 2 of the 5-HT3A receptor is a molecular determinant of allosteric modulation by 5-hydroxyindole

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