A-kinase anchoring in dendritic cells is required for antigen presentation.
BACKGROUND
Dendritic cells (DC) are the most potent antigen presenting cells (APC) of the immune system. Prostaglandin E(2), cyclic AMP, and protein kinase A (PKA) have all been shown to regulate DC maturation and activity. In other cells, the ability of these molecules to convey their signals has been shown to be dependent on A-kinase anchoring proteins (AKAPs). Here we present evidence for the existence and functional importance of AKAPs in human DC.


RESULTS
Using immunofluorescence and/or western analyses we identify AKAP79, AKAP149, AKAP95, AKAP LBC and Ezrin. We also demonstrate by western analysis that expression of AKAP79, AKAP149 and RII are upregulated with DC differentiation and maturation. We establish the functional importance of PKA anchoring in multiple aspects of DC biology using the anchoring inhibitor peptides Ht31 and AKAP-IS. Incubation of protein or peptide antigen loaded DC with Ht31 or AKAP-IS results in a 30-50% decrease in antigen presentation as measured by IFN-gamma production from antigen specific CD4(+) T cells. Incubation of LPS treated DC with Ht31 results in 80% inhibition of TNF-alpha and IL-10 production. Ht31 slightly decreases the expression of CD18 and CD11a and CD11b, slightly increases the basal expression of CD83, dramatically decreases the LPS stimulated expression of CD40, CD80 and CD83, and significantly increases the expression of the chemokine receptor CCR7.


CONCLUSIONS
These experiments represent the first evidence for the functional importance of PKA anchoring in multiple aspects of DC biology.
Schillace
Robynn V
RV
Portland Veterans Affairs Medical Center, Oregon Health and Science University, Portland, Oregon, United States of America.
Miller
Casey L
CL
Pisenti
Neal
N
Grotzke
Jeff E
JE
Swarbrick
Gwendolyn M
GM
Lewinsohn
David M
DM
Carr
Daniel W
DW
D054758:A Kinase Anchor Proteins / Q000037:antagonists & inhibitors / Q000502:physiology*; D000595:Amino Acid Sequence; D017951:Antigen Presentation / Q000502:physiology*; D015703:Antigens, CD / Q000096:biosynthesis / Q000235:genetics; D002454:Cell Differentiation; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D003713:Dendritic Cells / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D015232:Dinoprostone / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D008070:Lipopolysaccharides / Q000494:pharmacology; D008969:Molecular Sequence Data; D009000:Monocytes / Q000166:cytology / Q000187:drug effects; D011506:Proteins / Q000494:pharmacology; D054400:Receptors, CCR7 / Q000096:biosynthesis / Q000235:genetics; D013347:Subcellular Fractions / Q000737:chemistry; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D054758:A Kinase Anchor Proteins; D015703:Antigens, CD; C515370:CCR7 protein, human; C400224:Ht 31 protein, synthetic; D008070:Lipopolysaccharides; D011506:Proteins; D054400:Receptors, CCR7; D014409:Tumor Necrosis Factor-alpha; D017868:Cyclic AMP-Dependent Protein Kinases; D015232:Dinoprostone