title: α4β2 Nicotinic Acetylcholine Receptors: RELATIONSHIPS BETWEEN SUBUNIT STOICHIOMETRY AND FUNCTION AT THE SINGLE CHANNEL LEVEL.
abstract: Acetylcholine receptors comprising α4 and β2 subunits are the most abundant class of nicotinic acetylcholine receptor in the brain. They contribute to cognition, reward, mood, and nociception and are implicated in a range of neurological disorders. Previous measurements of whole-cell macroscopic currents showed that α4 and β2 subunits assemble in two predominant pentameric stoichiometries, which differ in their sensitivity to agonists, antagonists, and allosteric modulators. Here we compare agonist-elicited single channel currents from receptors assembled with an excess of either the α4 or β2 subunit, forming receptor populations biased toward one or the other stoichiometry, with currents from receptors composed of five concatemeric subunits in which the subunit stoichiometry is predetermined. Our results associate each subunit stoichiometry with a unique single channel conductance, mean open channel lifetime, and sensitivity to the allosteric potentiator 3-[3-(3-pyridinyl)-1,2,4-oxadiazol-5-yl]benzonitrile (NS-9283). Receptors with the composition (α4β2)2α4 exhibit high single channel conductance, brief mean open lifetime, and strong potentiation by NS-9283, whereas receptors with the composition (α4β2)2β2 exhibit low single channel conductance and long mean open lifetime and are not potentiated by NS-9283. Thus single channel current measurements reveal bases for the distinct functional and pharmacological properties endowed by different stoichiometries of α4 and β2 subunits and establish pentameric concatemers as a means to delineate interactions between subunits that confer these properties.
authors.affiliation: From the Receptor Biology Laboratory, Department of Physiology and Biomedical Engineering and.
authors.forename: Simone
authors.identifier: 0000-0003-4402-5325
authors.initials: S
authors.lastname: Mazzaferro
authors.affiliation: the School of Life Sciences, Oxford Brookes University, Oxford OX3 OBP, United Kingdom.
authors.forename: Isabel
authors.identifier: 0000-0001-7692-1509
authors.initials: I
authors.lastname: Bermudez
authors.affiliation: From the Receptor Biology Laboratory, Department of Physiology and Biomedical Engineering and sine@mayo.edu.|Departments of Neurology and.|Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, Minnesota 55905 and.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Sine
mesh_terms: D000818:Animals; D002460:Cell Line; D006801:Humans; D018722:Nicotinic Agonists / Q000494:pharmacology; D010069:Oxadiazoles / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D011725:Pyridines / Q000494:pharmacology; D011978:Receptors, Nicotinic / Q000737:chemistry / Q000378:metabolism*
chemical_list: C561896:3-(3-(pyridine-3-yl)-1,2,4-oxadiazol-5-yl)benzonitrile; D018722:Nicotinic Agonists; D010069:Oxadiazoles; D011725:Pyridines; D011978:Receptors, Nicotinic; C403531:nicotinic receptor alpha4beta2
keywords: 14-3-3 protein; allosteric regulation; conductance; nicotinic acetylcholine receptors (nAChR); patch clamp