Steel factor enhances supraoptimal antigen-induced IL-6 production from mast cells via activation of protein kinase C-beta.
Ag-triggered mast cell (MC) activation follows a bell-shaped dose-response curve. Reduced activation in response to supraoptimal Ag concentrations is thought to be due to preferential engagement of inhibitory-acting proteins like SHIP1, Lyn, and protein kinase C (PKC)-delta. We show in this study that short-term prestimulation with Steel factor (SF) prevents supraoptimal Ag inhibition, resulting in synergistic MC degranulation and IL-6 secretion. These events are preceded by synergistic phosphorylation/activation of numerous signaling proteins, e.g., Erk, p38, and LAT. However, these effects of prestimulation with SF appear not to be due to reduced engagement of the attenuator SHIP1. Pharmacological analyses suggest that the activation of conventional PKCs is important for this synergy. Specifically, although we found that the conventional PKC inhibitor, Gö6976, likely has some PKC-independent targets in MCs, it led us to further studies that established SF plus Ag-induced IL-6 secretion was severely impaired in PKC-beta(-/-) MCs, but not PKC-alpha(-/-) MCs. Thus, PKC-beta joins PI3K and Btk as important players in this synergistic MC activation.
Fehrenbach
Kerstin
K
Department of Molecular Immunology, Biology III, University of Freiburg and Max-Planck-Institute for Immunobiology, Albert-Ludwigs-University Freiburg, Freiburg, Germany.
Lessmann
Eva
E
Zorn
Carolin N
CN
Kuhny
Marcel
M
Grochowy
Gordon
G
Krystal
Gerald
G
Leitges
Michael
M
Huber
Michael
M
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000818:Animals; D000941:Antigens / Q000276:immunology*; D001853:Bone Marrow / Q000276:immunology; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation / Q000276:immunology; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000187:drug effects; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D015850:Interleukin-6 / Q000096:biosynthesis* / Q000276:immunology* / Q000378:metabolism; D007527:Isoenzymes / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D008297:Male; D008407:Mast Cells / Q000166:cytology / Q000187:drug effects / Q000201:enzymology* / Q000276:immunology*; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D010750:Phosphoproteins / Q000378:metabolism; D019000:Phosphotyrosine / Q000378:metabolism; D011493:Protein Kinase C / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D064546:Protein Kinase C beta; D019089:Stem Cell Factor / Q000494:pharmacology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D000941:Antigens; D015850:Interleukin-6; D007527:Isoenzymes; C491734:Lat protein, mouse; D008565:Membrane Proteins; D010750:Phosphoproteins; D019089:Stem Cell Factor; D019000:Phosphotyrosine; D011493:Protein Kinase C; D064546:Protein Kinase C beta; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D002118:Calcium