title: betac cytokine receptor-induced stimulation of cAMP response element binding protein phosphorylation requires protein kinase C in myeloid cells: a novel cytokine signal transduction cascade.
abstract: We have recently shown that IL-3R occupancy activates a phosphatidylcholine-specific phospholipase C, and the sustained diacylglycerol accumulation subsequently activates protein kinase C (PKC). In human IL-3-dependent myeloid cells (TF-1), the novel PKCepsilon isoform regulates bcl-2 expression and cell survival. The report of a PKC activatable cAMP response element (CRE) in the bcl-2 promoter and a role for PKC in bcl-2 expression in B cells led us to the hypothesis that PKC phosphorylation activates transcription factor CREB after IL-3R engagement. We found that IL-3 and GM-CSF induced phosphorylation of CREB on Ser(133) in TF-1 cells, and this phosphorylation was blocked by two structurally unrelated classes of PKC inhibitors. An inhibitor of cyclic nucleotide-dependent kinases did not block this phosphorylation. IL-4, which is biologically active in these cells but does not use the beta common subunit, did not phosphorylate CREB on Ser(133). Inhibition of mitogen-activated protein kinase kinase activity also inhibited IL3-induced CREB phosphorylation. The PKC inhibitors, but not a cyclic nucleotide-dependent kinase inhibitor, blocked IL-3 activation of CRE-dependent transcription from an egr-1 promoter/chloramphenicol acetyltransferase (CAT) reporter construction transiently transfected into TF-1 cells. Finally, TF-1 cells stably overexpressing PKCepsilon, but not the delta isoform of PKC, enhanced CRE-dependent CAT expression from the promoter/reporter construction. Therefore, it is likely that a PKCepsilon kinase cascade resulting in CREB phosphorylation represents a novel signal transduction cascade for regulating cellular gene expression through the beta common cytokine receptor.
authors.affiliation: Department of Immunology, Holland Laboratory/American Red Cross, Rockville, MD 20855, USA.
authors.forename: E
authors.initials: E
authors.lastname: Gubina
authors.forename: X
authors.initials: X
authors.lastname: Luo
authors.forename: E
authors.initials: E
authors.lastname: Kwon
authors.forename: K
authors.initials: K
authors.lastname: Sakamoto
authors.forename: Y F
authors.initials: YF
authors.lastname: Shi
authors.forename: R A
authors.initials: RA
authors.lastname: Mufson
mesh_terms: D000577:Amides / Q000494:pharmacology; D050882:CREB-Binding Protein; D000242:Cyclic AMP / Q000378:metabolism; D053648:Cytokine Receptor Common beta Subunit; D004268:DNA-Binding Proteins / Q000235:genetics; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D007377:Interleukin-3 / Q000494:pharmacology; D015847:Interleukin-4 / Q000494:pharmacology; D007527:Isoenzymes / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008957:Models, Genetic; D022423:Myeloid Cells / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D016185:Receptors, Interleukin-3 / Q000378:metabolism*; D020218:Response Elements; D015398:Signal Transduction; D015534:Trans-Activators / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D000577:Amides; C115876:CSF2RB protein, human; D053648:Cytokine Receptor Common beta Subunit; D004268:DNA-Binding Proteins; D007377:Interleukin-3; D007527:Isoenzymes; C440023:NPC 15342; D009687:Nuclear Proteins; D011956:Receptors, Cell Surface; D016185:Receptors, Interleukin-3; D015534:Trans-Activators; D014157:Transcription Factors; D015847:Interleukin-4; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D000242:Cyclic AMP; D050882:CREB-Binding Protein; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases