Identification of a novel human eicosanoid receptor coupled to G(i/o).
We have conducted an in silico data base search for and cloned a novel G-protein-coupled receptor (GPCR) named TG1019. Dot and Northern blotting analyses showed that transcripts of the novel GPCR were expressed in various tissues except brain, and the expression was more intense in liver, kidney, peripheral leukocyte, lung, and spleen than in other tissues. By GTP gamma S binding assay using the TG1019-G alpha(i1)-protein fusion expressed in insect cells, eicosanoids, and polyunsaturated fatty acids such as 5-oxo-6E,8Z,11Z,14Z-eicosatetraenoic acid (5-oxo-ETE), 5(S)-hydroperoxy-6E,8Z, 11Z,14Z-eicosatetraenoic acid, and arachidonic acid were identified to exhibit agonistic activities against TG1019. 5-oxo-ETE was the most potent to enhance the specific binding by 6-fold at a maximum effect dose of submicromolar to micromolar order with an ED(50) value of 5.7 nM. Conversely, polyunsaturated fatty acids such as docosahexaenoic acid and eicosapentaenoic acid showed antagonistic activities against TG1019. In Chinese hamster ovary cells transiently expressing TG1019, the forskolin-stimulated production of cAMP was inhibited up to approximately 70% by 5-oxo-ETE, with an IC(50) value of 33 nM. This inhibition was sensitive to pretreatment of the cells with pertussis toxin.
Hosoi
Takeshi
T
Discovery Research Laboratory, Tanabe Seiyaku Co. Ltd., 2-50 Kawagishi-2-chome, Toda-shi, Saitama 335-8505, Japan.
Koguchi
Yutaka
Y
Sugikawa
Emiko
E
Chikada
Aiko
A
Ogawa
Koji
K
Tsuda
Naoki
N
Suto
Naoki
N
Tsunoda
Shiho
S
Taniguchi
Tomoyasu
T
Ohnuki
Tetsuo
T
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002462:Cell Membrane / Q000502:physiology; D003001:Cloning, Molecular; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000235:genetics*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D020962:Heterotrimeric GTP-Binding Proteins / Q000378:metabolism*; D006801:Humans; D007313:Insecta; D008969:Molecular Sequence Data; D009928:Organ Specificity; D011487:Protein Conformation; D018055:Receptors, Eicosanoid / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014162:Transfection
D018055:Receptors, Eicosanoid; D011993:Recombinant Fusion Proteins; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D020962:Heterotrimeric GTP-Binding Proteins