The role of protein kinase A anchoring via the RII alpha regulatory subunit in the murine immune system.
Intracellular cAMP may inhibit T cell activation and proliferation via activation of the cAMP-dependent protein kinase, PKA. PKA signaling is maintained through interactions of the regulatory subunit with A-kinase anchoring proteins (AKAPs). We demonstrated that T cells contain AKAPs and now ask whether PKA anchoring to AKAPs via the RIIalpha regulatory subunit is necessary for cAMP-mediated inhibition of T cell activation. We studied the immune systems of mice lacking the RIIalpha regulatory subunit of PKA (-/-) and the ability of cells isolated from these mice to respond to cAMP. Dissection of spleen and thymus from wild-type (WT) and -/- mice, single cell suspensions generated from these organs, and flow cytometry analysis illustrate that the gross morphology, cell numbers, and cell populations in the spleen and thymus of the -/- mice are similar to WT controls. In vitro, splenocytes from -/- mice respond to anti-CD3/anti-CD28 and PMA/ionomycin stimulation and produce IL-2 similar to WT. Cytokine analysis revealed no significant difference in Th1 or Th2 differentiation. Finally, equivalent frequencies of CD8(+) IFN-gamma producing effector cells were stimulated upon infection of WT or -/- mice with Listeria monocytogenes. These data represent the first study of the role of RIIalpha in the immune system in vivo and provide evidence that T cell development, homeostasis, and the generation of a cell-mediated immune response are not altered in the RIIalpha -/- mice, suggesting either that RIIalpha is not required for normal immune function or that other proteins are able to compensate for RIIalpha function.
Schillace
Robynn V
RV
Veterans Affairs Medical Center, Department of Endocrinology, Oregon Health and Science University, Portland, 97239, USA.
Andrews
Sarah F
SF
Galligan
Sarah G
SG
Burton
Kimberly A
KA
Starks
Holly J
HJ
Bouwer
H G Archie
HG
McKnight
G Stanley
GS
Davey
Michael P
MP
Carr
Daniel W
DW
D054758:A Kinase Anchor Proteins; D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism* / Q000502:physiology; D000818:Animals; D015153:Blotting, Western; D018106:CD28 Antigens / Q000276:immunology; D017252:CD3 Complex / Q000276:immunology; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D054754:Cyclic AMP-Dependent Protein Kinase RIIalpha Subunit; D017868:Cyclic AMP-Dependent Protein Kinases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D007106:Immune Sera / Q000494:pharmacology; D007527:Isoenzymes / Q000172:deficiency / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D008088:Listeriosis / Q000201:enzymology / Q000235:genetics / Q000276:immunology; D008213:Lymphocyte Activation / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009928:Organ Specificity / Q000235:genetics / Q000276:immunology; D021122:Protein Subunits / Q000378:metabolism / Q000502:physiology; D013154:Spleen / Q000166:cytology / Q000201:enzymology* / Q000276:immunology*; D018417:Th1 Cells / Q000166:cytology / Q000201:enzymology / Q000276:immunology; D018418:Th2 Cells / Q000166:cytology / Q000201:enzymology / Q000276:immunology; D013950:Thymus Gland / Q000166:cytology / Q000201:enzymology* / Q000276:immunology*
D054758:A Kinase Anchor Proteins; D048868:Adaptor Proteins, Signal Transducing; C486333:Akap1 protein, mouse; D018106:CD28 Antigens; D017252:CD3 Complex; D054754:Cyclic AMP-Dependent Protein Kinase RIIalpha Subunit; D007106:Immune Sera; D007527:Isoenzymes; C517821:Prkar2a protein, mouse; D021122:Protein Subunits; D017868:Cyclic AMP-Dependent Protein Kinases