UMMS Affiliation

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

Publication Date


Document Type



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


Biochemistry | Biochemistry, Biophysics, and Structural Biology | Molecular Biology


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.


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

Journal/Book/Conference Title

Proceedings of the National Academy of Sciences of the United States of America

Related Resources

Link to Article in PubMed

PubMed ID