OLIGODEOXYNUCLEOTIDES ANTISENSE TO MESSENGER-RNA ENCODING PROTEIN-KINASE-A, PROTEIN-KINASE-C, AND BETA-ADRENERGIC-RECEPTOR KINASE REVEAL DISTINCTIVE CELL-TYPE-SPECIFIC ROLES IN AGONIST-INDUCED DESENSITIZATION

The roles of three protein kinases, cyclic AMP-dependent protein kinas e (protein kinase A), protein kinase C, and beta-adrenergic receptor k inase (beta ARK), implicated in agonist-induced desensitization of gua nine nucleotide-binding protein (G-protein)-coupled receptors were exp lored in four different cell lines after 48 hr of incubation with olig odeoxynucleotides antisense to the mRNA encoding each kinase. Desensit ization of beta(2)-adrenergic receptors was analyzed in cell types in which the activities of the endogenous complement of protein kinases A and C and beta ARK were distinctly different. Protein kinase A was ne cessary for desensitization of rat osteosarcoma cells (ROS 17/2.8), wh ereas the contribution of beta ARK to desensitization was insignifican t. In Chinese hamster ovary cells that stably express beta(2)-adrenerg ic receptors and in smooth muscle cells (DDT(1)MF-2), oligodeoxynucleo tides antisense to beta ARK mRNA nearly abolished desensitization, whe reas oligodeoxynucleotides antisense to protein kinase A mRNA attenuat ed desensitization to a lesser extent. In human epidermoid carcinoma c ells (A-431), oligodeoxynucleotides antisense to either protein kinase A mRNA or beta ARK mRNA attenuated agonist-induced desensitization, p roviding a third scenario in which two kinases constitute the basis fo r agonist-induced desensitization. In sharp contrast, oligodeoxynucleo tides antisense to protein kinase C mRNA were found to enhance rather than attenuate desensitization in DDT(1)MF-2 and A-431 cell lines, dem onstrating counterregulation between prominent protein kinases in dese nsitization. Using antisense oligodeoxynucleotides to ''knock out'' ta rget protein kinases in vivo, we reveal distinctive cell-type-specific roles of protein kinase A, protein kinase C, and beta ARK in agonist- induced desensitization.