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Multiple Coupling of Human D5 Dopamine Receptors to Guanine Nucleotide Binding Proteins G S and G z
Author(s) -
Sidhu Anita,
Kimura Kazuhiro,
Uh Misook,
White Beatrix H.,
Patel Shutish
Publication year - 1998
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1998.70062459.x
Subject(s) - receptor , g protein , cholera toxin , dopamine receptor , gs alpha subunit , adenylyl cyclase , pertussis toxin , d2 like receptor , biology , rhodopsin like receptors , g protein coupled receptor , heterotrimeric g protein , alpha (finance) , microbiology and biotechnology , biochemistry , agonist , endocrinology , metabotropic receptor , dopamine receptor d1 , medicine , construct validity , nursing , patient satisfaction
We have demonstrated previously that D1 dopamine receptors are coupled to both G s α and G o α. We examine here the coupling between human D5 dopamine receptors and G proteins in transfected rat pituitary GH 4 C 1 cells. Similar to D1 receptors, cholera toxin treatment of cells reduced, but did not abolish, D5 agonist high‐affinity binding sites, indicating D5 receptors couple to both G s α and cholera toxin‐insensitive G proteins. The interaction between D5 receptors and G s α was confirmed by immunoprecipitation studies and by the ability of D5 receptors to stimulate adenylyl cyclase. Unlike D1 receptors, D5 receptors did not display any pertussis toxin‐sensitive G‐protein coupling to G o α or G i α. D5 receptors were also not coupled to G q α and were unable to mediate phosphatidylinositol metabolism. Instead, D5 sites appeared to be coupled to an AIF − 4 ‐sensitive, N ‐ethylmaleimide‐resistant G protein. Anti‐G z α caused immunoprecipitation of 24.2 ± 5.2% of G protein‐associated D5 receptors, indicating coupling between D5 and G z α. The coupling to G z α was specific for D5 receptors, because similar associations were not detected between D1 receptors and G z α.