title: Single nucleotide polymorphism of human platelet-activating factor receptor impairs G-protein activation.
abstract: Various proinflammatory and vasoactive actions of platelet-activating factor (PAF) are mediated through a specific G-protein-coupled PAF receptor (PAFR). We identified a novel DNA variant in the human PAFR gene, which substitutes an aspartic acid for an alanine residue at position 224 (A224D) in the putative third cytoplasmic loop. This mutation was observed in a Japanese population at an allele frequency of 7.8%. To delineate the functional consequences of this structural alteration, Chinese hamster ovary cells were stably transfected with constructs encoding either wild-type or A224D mutated PAFR. No significant difference was observed in the expression level of the receptor or the affinity to PAF or to an antagonist, WEB2086, between the cells transfected with wild-type and mutant PAFR. Chinese hamster ovary cells expressing A224D mutant PAFR displayed partial but significant reduction of PAF-induced intracellular signals such as calcium mobilization, inositol phosphate production, inhibition of adenylyl cyclase, and chemotaxis. These findings suggest that this variant receptor produced by a naturally occurring mutation exhibits impaired coupling to G-proteins and may be a basis for interindividual variation in PAF-related physiological responses, disease predisposition or phenotypes, and drug responsiveness.
authors.affiliation: Department of Medicine, Keio University School of Medicine, Tokyo 160-8582, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Fukunaga
authors.forename: S
authors.initials: S
authors.lastname: Ishii
authors.forename: K
authors.initials: K
authors.lastname: Asano
authors.forename: T
authors.initials: T
authors.lastname: Yokomizo
authors.forename: T
authors.initials: T
authors.lastname: Shiomi
authors.forename: T
authors.initials: T
authors.lastname: Shimizu
authors.forename: K
authors.initials: K
authors.lastname: Yamaguchi
mesh_terms: D037361:Adenylate Cyclase Toxin; D000067956:Adenylyl Cyclase Inhibitors; D000409:Alanine / Q000737:chemistry; D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D001224:Aspartic Acid / Q000737:chemistry; D001381:Azepines / Q000494:pharmacology; D016466:CHO Cells; D002460:Cell Line; D002633:Chemotaxis; D005576:Colforsin / Q000494:pharmacology; D006224:Cricetinae; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006801:Humans; D007295:Inositol Phosphates / Q000378:metabolism; D007700:Kinetics; D008024:Ligands; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D010980:Platelet Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism*; D011110:Polymorphism, Genetic; D020641:Polymorphism, Single Nucleotide; D011485:Protein Binding; D011869:Radioligand Assay; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D015398:Signal Transduction; D014162:Transfection; D014230:Triazoles / Q000494:pharmacology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: D037361:Adenylate Cyclase Toxin; D000067956:Adenylyl Cyclase Inhibitors; D001381:Azepines; D007295:Inositol Phosphates; D008024:Ligands; D010975:Platelet Aggregation Inhibitors; D010980:Platelet Membrane Glycoproteins; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D014230:Triazoles; D010566:Virulence Factors, Bordetella; C039351:platelet activating factor receptor; C052518:WEB 2086; D005576:Colforsin; D001224:Aspartic Acid; D000242:Cyclic AMP; D019204:GTP-Binding Proteins; D000409:Alanine