PKCtheta and PKA are antagonistic partners in the NF-AT transactivation pathway of primary mouse CD3+ T lymphocytes.
We here investigate the crosstalk of PKC and PKA signaling during primary CD3(+) T-lymphocyte activation using pharmacologic inhibitors and activators in combination with our established panel of PKC isotype-deficient mouse T cells in vitro. PKCtheta and PKA inversely affect the CD3/CD28-induced IL-2 expression, whereas other PKC isotypes are dispensable in this signaling pathway. Gene ablation of PKCtheta selectively results in a profound reduction of IL-2 production; however, complete abrogation of IL-2 production in these PKCtheta(-/-) T cells was achieved only by simultaneous coactivation of the cAMP/PKA pathway in CD3(+) T cells. Conversely, the reduced IL-2 production in PKC inhibitor-treated T cells can be rescued by inhibition of the cAMP/PKA pathway in wild-type but not in PKCtheta(-/-) T cells. Mechanistically, the cAMP/PKA and PKCtheta pathways converge at the level of NF-AT, as shown by DNA binding analysis. The combined increase in PKA and decrease in PKCtheta activity leads to an enhanced inhibition of nuclear NF-AT translocation. This PKCtheta/PKA crosstalk significantly affects neither the NF-kappaB, the AP-1, nor the CREB pathways. Taken together, this opposite effect between the positive PKCtheta and the negative cAMP/PKA signaling pathways appears rate limiting for NF-AT transactivation and IL-2 secretion responses of CD3(+) T lymphocytes.
Hermann-Kleiter
Natascha
N
Department of Medical Genetics, Molecular and Clinical Pharmacology, Innsbruck Medical University, Schoepfstr 41, A-6020 Innsbruck, Austria.
Thuille
Nikolaus
N
Pfeifhofer
Christa
C
Gruber
Thomas
T
Schäfer
Michaela
M
Zitt
Christof
C
Hatzelmann
Armin
A
Schudt
Christian
C
Leitges
Michael
M
Baier
Gottfried
G
D021581:Active Transport, Cell Nucleus / Q000187:drug effects / Q000235:genetics / Q000276:immunology; D000818:Animals; D018106:CD28 Antigens / Q000276:immunology; D017252:CD3 Complex / Q000276:immunology*; D050882:CREB-Binding Protein / Q000276:immunology; D002467:Cell Nucleus / Q000276:immunology; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000276:immunology; D017868:Cyclic AMP-Dependent Protein Kinases; D017353:Gene Deletion; D007376:Interleukin-2 / Q000276:immunology; D008213:Lymphocyte Activation / Q000187:drug effects / Q000235:genetics / Q000276:immunology; D051379:Mice; D016328:NF-kappa B / Q000276:immunology; D050778:NFATC Transcription Factors / Q000276:immunology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000276:immunology*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000276:immunology*; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics / Q000276:immunology*; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D018808:Transcription Factor AP-1 / Q000276:immunology
D018106:CD28 Antigens; D017252:CD3 Complex; D007376:Interleukin-2; D016328:NF-kappa B; D050778:NFATC Transcription Factors; D047428:Protein Kinase Inhibitors; D018808:Transcription Factor AP-1; D000242:Cyclic AMP; D050882:CREB-Binding Protein; C494364:Crebbp protein, mouse; D017346:Protein Serine-Threonine Kinases; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C