Differential desensitization and phosphorylation of three cloned and transfected alpha 2-adrenergic receptor subtypes.

Published

Journal Article

Genes encoding 3 distinct subtypes of human alpha 2-adrenergic receptor are known and are found, respectively, on chromosome 10, 4, and 2 (alpha 2-C10, alpha 2-C4, and alpha 2-C2 adrenergic receptors). All 3 receptors inhibit adenylyl cyclase via Gi proteins. To study and compare their regulatory properties we assessed the ability of each to undergo agonist-promoted desensitization and phosphorylation. When Chinese hamster ovary cells stably expressing each of the three receptor genes were incubated with epinephrine for 20 min, a marked decrease in sensitivity to subsequent agonist-mediated inhibition of adenylyl cyclase was observed for the alpha 2-C10 and alpha 2-C2 receptors but not for the alpha 2-C4 receptors. When similar incubations were performed with 32Pi-labeled cells and the receptors were immunoprecipitated with specific antibodies, alpha 2-C10 and alpha 2-C2 receptors were found to undergo an approximately 3-fold increase in receptor phosphorylation after epinephrine exposure. When transfected into COS cells epinephrine also stimulated phosphorylation of alpha 2-C10 and alpha 2-C2 receptors while having only a slight effect on alpha 2-C4 receptors. Cotransfection of the cells with the cDNA encoding the beta-adrenergic receptor kinase further increased receptor phosphorylation for alpha 2-C10 and alpha 2-C2 receptors while having little or no effect on alpha 2-C4 receptors. Moreover purified and reconstituted recombinant alpha 2-C10 receptors could be phosphorylated in an agonist-dependent fashion whereas alpha 2-C4 receptors could not. These observations suggest receptor subtype-specific differences in susceptibility to regulatory phosphorylation and desensitization.

Full Text

Duke Authors

Cited Authors

  • Kurose, H; Lefkowitz, RJ

Published Date

  • April 1, 1994

Published In

Volume / Issue

  • 269 / 13

Start / End Page

  • 10093 - 10099

PubMed ID

  • 7908287

Pubmed Central ID

  • 7908287

International Standard Serial Number (ISSN)

  • 0021-9258

Language

  • eng

Conference Location

  • United States