title: Defining the putative inhibitory site for a selective negative allosteric modulator of human α4β2 neuronal nicotinic receptors.
abstract: Neuronal nicotinic receptors (nAChRs) have been implicated in several diseases and disorders such as autism spectrum disorders, Alzheimer's disease, Parkinson's disease, epilepsy, and nicotine addiction. To understand the role of nAChRs in these conditions, it would be beneficial to have selective molecules that target specific nAChRs in vitro and in vivo. Our laboratory has previously identified a novel allosteric site on human α4β2 nAChRs using a series of computational and in vitro approaches. At this site, we have identified negative allosteric modulators that selectively inhibit human α4β2 nAChRs, a subtype implicated in nicotine addiction. This study characterizes the allosteric site via site-directed mutagenesis. Three amino acids (Phe118, Glu60, and Thr58) on the β2 subunit were shown to participate in the inhibitory properties of the selective antagonist KAB-18 and provided insights into its antagonism of human α4β2 nAChRs. SAR studies with KAB-18 analogues and various mutant α4β2 nAChRs also provided information concerning how different physiochemical features influence the inhibition of nAChRs through this allosteric site. Together, these studies identify the amino acids that contribute to the selective antagonism of human α4β2 nAChRs at this allosteric site. Finally, these studies define the physiochemical features of ligands that influence interaction with specific amino acids in this allosteric site.
authors.affiliation: Division of Biology, California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: Brandon J
authors.initials: BJ
authors.lastname: Henderson
authors.forename: Tatiana F
authors.initials: TF
authors.lastname: González-Cestari
authors.forename: Bitna
authors.initials: B
authors.lastname: Yi
authors.forename: Ryan E
authors.initials: RE
authors.lastname: Pavlovicz
authors.forename: R Thomas
authors.initials: RT
authors.lastname: Boyd
authors.forename: Chenglong
authors.initials: C
authors.lastname: Li
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Bergmeier
authors.forename: Dennis B
authors.initials: DB
authors.lastname: McKay
mesh_terms: D001665:Binding Sites; D001713:Biphenyl Compounds / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D009154:Mutation / Q000235:genetics / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D018733:Nicotinic Antagonists / Q000378:metabolism* / Q000494:pharmacology*; D010649:Phenylalanine / Q000737:chemistry; D010880:Piperidines / Q000494:pharmacology*; D011978:Receptors, Nicotinic / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D013329:Structure-Activity Relationship; D013912:Threonine / Q000737:chemistry
chemical_list: D001713:Biphenyl Compounds; C579803:KAB-18; D018733:Nicotinic Antagonists; D010880:Piperidines; D011978:Receptors, Nicotinic; C403531:nicotinic receptor alpha4beta2; D013912:Threonine; D010649:Phenylalanine; D002118:Calcium