Functional coupling of a recombinant human 5-HT5A receptor to G-proteins in HEK-293 cells.
1. We have cloned, expressed and pharmacologically characterized the Human 5-HT5A receptor. 2. We have shown that ligand activation of the Human 5-HT5A receptor results in functional coupling to G-proteins in HEK-293 cells. 3. Stimulation of the receptor with 5-CT (5-carboxamidotryptamine) resulted in a dose-dependent increase in the % [35S]-GTPgammaS binding over the basal level. This is the first study to describe such G-protein activation for the Human 5-HT5A receptor in any cell. 4. A dose-dependent inhibition of cyclic AMP accumulation was observed in the recombinant Human 5-HT5A receptor cell line, suggesting a functional coupling to a G alpha i, G-protein in the HEK-293 cell line. 5. A ligand-stimulated reduction in the detectable level of the catalytic domain of protein kinase A (PKA) in nuclear extracts isolated from Human 5-HT5A expressing cells was observed. This observation was consistent with the reduction in the level of cyclic AMP accumulation, in response to receptor activation.
National Agriculture and Veterinary Biotechnology Centre and Department of Pharmacology, University College Dublin, Belfield, Ireland.
P T
PT
Hurley
R A
RA
McMahon
P
P
Fanning
K M
KM
O'Boyle
M
M
Rogers
F
F
Martin
D000595:Amino Acid Sequence; D001483:Base Sequence; D020134:Catalytic Domain; D002460:Cell Line; D002467:Cell Nucleus / Q000201:enzymology; D003001:Cloning, Molecular; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D017931:DNA Primers; D018076:DNA, Complementary; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D011485:Protein Binding; D011985:Receptors, Serotonin / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012701:Serotonin / Q000031:analogs & derivatives / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology
D017931:DNA Primers; D018076:DNA, Complementary; D011985:Receptors, Serotonin; D011994:Recombinant Proteins; D017366:Serotonin Receptor Agonists; C078730:serotonin 5 receptor; D005576:Colforsin; D012701:Serotonin; C047087:5-carboxamidotryptamine; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D019204:GTP-Binding Proteins