title: Exploring the determinants of trace amine-associated receptor 1's functional selectivity for the stereoisomers of amphetamine and methamphetamine.
abstract: Amphetamines are widely abused drugs that interfere with dopamine transport and storage. Recently, however, another mechanism of action was identified: stereoselective activation of the GαS protein-coupled trace amine-associated receptor 1 (TAAR1). To identify structural determinants of this stereoselectivity, we functionally evaluated six mutant receptors in vitro and then used homology modeling and dynamic simulation to predict drug affinities. Converting Asp102 to Ala rendered mouse and rat TAAR1 (mTAAR1 and rTAAR1, respectively) insensitive to β-phenylethylamine, amphetamine (AMPH), and methamphetamine (METH). Mutating Met268 in rTAAR1 to Thr shifted the concentration-response profiles for AMPH and METH isomers rightward an order of magnitude, whereas replacing Thr268 with Met in mTAAR1 resulted in profiles leftward shifted 10-30-fold. Replacing Asn287 with Tyr in rTAAR1 produced a mouselike receptor, while the reciprocal mTAAR1 mutant was rTAAR1-like. These results confirm TAAR1 is an AMPH/METH receptor in vitro and establish residues 102 (3.32) and 268 (6.55) as major contributors to AMPH/METH binding with residue 287 (7.39) determining species stereoselectivity.
authors.affiliation: Department of Physiology & Pharmacology, School of Medicine, Oregon Health & Science University , Portland, Oregon 97239, United States.
authors.forename: Edmund A
authors.initials: EA
authors.lastname: Reese
authors.forename: Yohei
authors.initials: Y
authors.lastname: Norimatsu
authors.forename: Madeline S
authors.initials: MS
authors.lastname: Grandy
authors.forename: Katherine L
authors.initials: KL
authors.lastname: Suchland
authors.forename: James R
authors.initials: JR
authors.lastname: Bunzow
authors.forename: David K
authors.initials: DK
authors.lastname: Grandy
mesh_terms: D000595:Amino Acid Sequence; D000661:Amphetamine / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D001665:Binding Sites; D000697:Central Nervous System Stimulants / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D000242:Cyclic AMP / Q000096:biosynthesis; D057809:HEK293 Cells; D006801:Humans; D008694:Methamphetamine / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D051379:Mice; D062105:Molecular Docking Simulation; D056004:Molecular Dynamics Simulation; D008969:Molecular Sequence Data; D009154:Mutation; D051381:Rats; D043562:Receptors, G-Protein-Coupled / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013237:Stereoisomerism; D000095383:Trace Amine-Associated Receptors
chemical_list: D000661:Amphetamine; D000697:Central Nervous System Stimulants; D000242:Cyclic AMP; D008694:Methamphetamine; D043562:Receptors, G-Protein-Coupled; D000095383:Trace Amine-Associated Receptors