UMMS Affiliation

Department of Biochemistry and Molecular Pharmacology, Department of Neurobiology University of Massachusetts Medical School



Document Type


Medical Subject Headings

Adenylate Cyclase; Animals; Dose-Response Relationship, Drug; Electrophoresis, Polyacrylamide Gel; Erythrocytes; *Guanosine 5'-O-(3-Thiotriphosphate); Guanosine Triphosphate; Isoproterenol; Phorbols; Phosphorylation; Receptors, Adrenergic, beta; Tetradecanoylphorbol Acetate; Thionucleotides; Time Factors; Turkeys


Incubation of turkey erythrocytes with the phorbol ester phorbol 12-myristate 13-acetate (PMA) results in a dose- and time-dependent desensitization of isoproterenol-stimulated adenylate cyclase activity. Compared to controls, membranes from PMA-treated cells have an isoproterenol-stimulated adenylate cyclase activity that is decreased 20%-40%, with little effect on forskolin or fluoride activation of adenylate cyclase. No change in beta-adrenergic receptor number is observed after PMA treatment, indicating that the major effect of PMA is to uncouple receptor interactions with Ns, the stimulatory guanine nucleotide regulatory protein of adenylate cyclase. Purification of beta-adrenergic receptors from 32Pi-labeled turkey erythrocytes, incubated in the presence or absence of PMA, indicates that the phorbol ester is capable of inducing a 3-fold increase in phosphorylation of the beta-adrenergic receptor. The PMA effect is similar to the phosphorylation of the beta-adrenergic receptor during isoproterenol- and dibutyryl cAMP-induced desensitization of adenylate cyclase in turkey erythrocytes. The findings indicate that decreased receptor-Ns coupling is correlated with receptor phosphorylation and that phorbol esters can influence the responsiveness of hormone-sensitive adenylate cyclase in certain cell types.

Rights and Permissions

Citation: Proc Natl Acad Sci U S A. 1984 Jul;81(14):4316-20. Link to article on publisher's website

Related Resources

Link to Article in PubMed



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.