title: A missense mutation in the seven-transmembrane domain of the human Ca2+ receptor converts a negative allosteric modulator into a positive allosteric modulator.
abstract: G protein-coupled receptors (GPCRs) are the most common targets of drug action. Allosteric modulators bind to the seven-transmembrane domain of family 3 GPCRs and offer enhanced selectivity over orthosteric ligands that bind to the large extracellular N terminus. We characterize a novel negative allosteric modulator of the human Ca(2+) receptor, Compound 1, that retains activity against the E837A mutant that lacks a response to previously described positive and negative modulators. A related compound, JKJ05, acts as a negative allosteric modulator on the wild type receptor but as a positive modulator on the E837A mutant receptor. This positive modulation critically depends on the primary amine in JKJ05, which appears to interact with acidic residue Glu(767) in our model of the seven-transmembrane domain of the receptor. Our results suggest the need for identification of possible genetic variation in the allosteric site of therapeutically targeted GPCRs.
authors.affiliation: Molecular Pathophysiology Section, NIDCD, National Institutes of Health, Bethesda, Maryland 20892. Electronic address: jianxinh@intra.niddk.nih.gov.
authors.forename: Jianxin
authors.initials: J
authors.lastname: Hu
authors.affiliation: Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: Jiankang
authors.initials: J
authors.lastname: Jiang
authors.affiliation: Computational Chemistry Core Laboratory, NIDDK, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: Stefano
authors.initials: S
authors.lastname: Costanzi
authors.affiliation: Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: Craig
authors.initials: C
authors.lastname: Thomas
authors.affiliation: Bristol-Myers Squibb Pharmaceutical Research Institute, Princeton, New Jersey 08543.
authors.forename: Wu
authors.initials: W
authors.lastname: Yang
authors.affiliation: Bristol-Myers Squibb Pharmaceutical Research Institute, Princeton, New Jersey 08543.
authors.forename: Jean H M
authors.initials: JHM
authors.lastname: Feyen
authors.affiliation: Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Jacobson
authors.affiliation: Molecular Pathophysiology Section, NIDCD, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: Allen M
authors.initials: AM
authors.lastname: Spiegel
mesh_terms: D000495:Allosteric Site; D002118:Calcium / Q000737:chemistry*; D002460:Cell Line; D018698:Glutamic Acid / Q000737:chemistry; D006801:Humans; D006868:Hydrolysis; D008024:Ligands; D008956:Models, Chemical; D008958:Models, Molecular; D009154:Mutation; D020125:Mutation, Missense; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D044169:Receptors, Calcium-Sensing / Q000737:chemistry* / Q000235:genetics*; D014162:Transfection
chemical_list: D008024:Ligands; D044169:Receptors, Calcium-Sensing; D018698:Glutamic Acid; D002118:Calcium