Perturbation of the expression of the catalytic subunit C alpha of cyclic AMP-dependent protein kinase inhibits TCR-triggered secretion of IL-2 by T helper hybridoma cells.
The role of cAMP-dependent protein kinase (PKA) in the regulation of TCR-triggered IL-2 secretion was studied by transfecting T hybridoma cells with cDNA encoding the inhibitory regulatory subunit (RI alpha) of PKA with mutations in cAMP-binding sites (RI alpha(m)) or by pretreating T cells with catalytic subunit-alpha (C alpha) antisense mRNA oligonucleotides. Transfected RI alpha(m) was expected to compete with endogenous regulatory subunits and to irreversibly inactivate the catalytic subunit in RI alpha(m)-C alpha complexes. It was shown that C alpha and RI alpha are the major PKA subunits in T cells, thereby justifying the choice of RI alpha(m) and C alpha antisense oligos to modulate PKA activity in T lymphocytes. Perturbation of the expression of PKA subunits by RI alpha(m) resulted in transfectants with 1) no changes in basal PKA activity but inhibited cAMP-inducible PKA activity or 2) inhibited basal PKA activity but unaffected cAMP-inducible PKA activity. Transfectants with inhibited basal PKA activity had changed (inhibited) levels of TCR-triggered IL-2 production. The anti-C alpha antisense mRNA oligomers also inhibited basal PKA activity and TCR-triggered production of IL-2. The experiments described here and recently reported studies of the effects of C alpha inactivation on CTL effector functions and IFN-gamma secretion suggest that basal PKA activity could be required for the propagation of TCR-triggered signals needed for lymphokine secretion by T cells.
Sugiyama
H
H
Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
Chen
P
P
Hunter
M G
MG
Sitkovsky
M V
MV
D000818:Animals; D002384:Catalysis; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors* / Q000096:biosynthesis* / Q000494:pharmacology; D006825:Hybridomas; D007376:Interleukin-2 / Q000037:antagonists & inhibitors* / Q000096:biosynthesis*; D051379:Mice; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D011948:Receptors, Antigen, T-Cell / Q000037:antagonists & inhibitors*; D006377:T-Lymphocytes, Helper-Inducer / Q000187:drug effects*; D014162:Transfection / Q000235:genetics
D007376:Interleukin-2; D016376:Oligonucleotides, Antisense; D011948:Receptors, Antigen, T-Cell; D017868:Cyclic AMP-Dependent Protein Kinases