PPARgamma1 attenuates cytosol to membrane translocation of PKCalpha to desensitize monocytes/macrophages.
Recently, we provided evidence that PKCalpha depletion in monocytes/macrophages contributes to cellular desensitization during sepsis. We demonstrate that peroxisome proliferator-activated receptor gamma (PPARgamma) agonists dose dependently block PKCalpha depletion in response to the diacylglycerol homologue PMA in RAW 264.7 and human monocyte-derived macrophages. In these cells, we observed PPARgamma-dependent inhibition of nuclear factor-kappaB (NF-kappaB) activation and TNF-alpha expression in response to PMA. Elucidating the underlying mechanism, we found PPARgamma1 expression not only in the nucleus but also in the cytoplasm. Activation of PPARgamma1 wild type, but not an agonist-binding mutant of PPARgamma1, attenuated PMA-mediated PKCalpha cytosol to membrane translocation. Coimmunoprecipitation assays pointed to a protein-protein interaction of PKCalpha and PPARgamma1, which was further substantiated using a mammalian two-hybrid system. Applying PPARgamma1 mutation and deletion constructs, we identified the hinge helix 1 domain of PPARgamma1 that is responsible for PKCalpha binding. Therefore, we conclude that PPARgamma1-dependent inhibition of PKCalpha translocation implies a new model of macrophage desensitization.
von Knethen
Andreas
A
Institute of Biochemistry I, Faculty of Medicine, Johann Wolfgang Goethe University, 60590 Frankfurt, Theodor-Stern-Kai 7, Germany. v_knethen@zbc.kgu.de
Soller
Mathias
M
Tzieply
Nico
N
Weigert
Andreas
A
Johann
Axel M
AM
Jennewein
Carla
C
Köhl
Roman
R
Brüne
Bernhard
B
D000818:Animals; D001665:Binding Sites; D015415:Biomarkers / Q000032:analysis; D019556:COS Cells; D002462:Cell Membrane / Q000201:enzymology*; D002522:Chlorocebus aethiops; D003600:Cytosol / Q000201:enzymology; D006801:Humans; D008264:Macrophages / Q000201:enzymology*; D008954:Models, Biological; D009154:Mutation; D047495:PPAR gamma / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D051571:Protein Kinase C-alpha / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000502:physiology; D015398:Signal Transduction; D020798:Two-Hybrid System Techniques
D015415:Biomarkers; D047495:PPAR gamma; D051571:Protein Kinase C-alpha