IL-3-induced enhancement of retinoic acid receptor activity is mediated through Stat5, which physically associates with retinoic acid receptors in an IL-3-dependent manner.
The regulation of hematopoiesis involves the interaction of specific hematopoietic cytokines with lineage-specific transcription factors, but little is known about how these cytokines might regulate the expression/activity of these different transcription factors. Here we identify the critical signal transduction pathways that mediate the interleukin 3 (IL-3)-induced enhancement of retinoic acid receptor (RAR) transcriptional activity that accompanies the IL-3-mediated commitment of the multipotent, stem cell factor (SCF)-dependent EML cell line to granulocyte/monocyte progenitors. We observe that the addition of IL-3 to EML cells induces activation of the phosphatidylinositol-3 kinase, mitogen-activated protein kinase, and Jak/Stat pathways and that Jak2 activation is the critical "proximal" mediator of the IL-3-induced enhancement of RAR activity. Constitutively active Stat5 constructs enhance both the transcriptional activity of RARs in EML cells and the commitment of these cells to granulocyte/monocyte progenitors, whereas dominant-negative Stat5 constructs inhibit this IL-3-induced enhancement of RAR transcriptional activity. We observe that the retinoic acid response element (RARE) used in our RA responsive reporter harbors overlapping Stat/RAR-binding sites. Moreover, coimmunoprecipitation studies indicate an interaction between Stat5 and RARs that is IL-3 dependent. Thus, Stat5 is an important mediator of the IL-3-induced enhancement of RAR transcriptional activity that accompanies the commitment of immature EML cells to the granulocyte/monocyte lineage. Cytokine-mediated physical and functional interactions between Stat5 and RARs may play critical roles in regulating different stages of hematopoiesis.
Si
Jutong
J
Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
Collins
Steven J
SJ
D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D019070:Cell Lineage; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D024202:Electrophoretic Mobility Shift Assay; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D017930:Genes, Reporter; D006098:Granulocytes / Q000166:cytology; D006410:Hematopoiesis / Q000502:physiology; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects*; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology*; D053614:Janus Kinase 2; D020935:MAP Kinase Signaling System / Q000187:drug effects; D051379:Mice; D008894:Milk Proteins; D009000:Monocytes / Q000166:cytology; D019869:Phosphatidylinositol 3-Kinases / Q000187:drug effects / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011401:Promoter Regions, Genetic; D025941:Protein Interaction Mapping; D011505:Protein-Tyrosine Kinases / Q000502:physiology; D011518:Proto-Oncogene Proteins; D018168:Receptors, Retinoic Acid / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D011993:Recombinant Fusion Proteins / Q000502:physiology; D000072482:Retinoic Acid Receptor alpha; D047488:Retinoid X Receptors; D050799:STAT5 Transcription Factor; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D019089:Stem Cell Factor / Q000494:pharmacology; D015534:Trans-Activators / Q000235:genetics / Q000502:physiology*; D014157:Transcription Factors / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D014158:Transcription, Genetic / Q000187:drug effects / Q000502:physiology; D014212:Tretinoin / Q000378:metabolism
D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D007377:Interleukin-3; D053614:Janus Kinase 2; D008894:Milk Proteins; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011505:Protein-Tyrosine Kinases; D011518:Proto-Oncogene Proteins; D018168:Receptors, Retinoic Acid; D011993:Recombinant Fusion Proteins; D000072482:Retinoic Acid Receptor alpha; D047488:Retinoid X Receptors; D050799:STAT5 Transcription Factor; D019089:Stem Cell Factor; D015534:Trans-Activators; D014157:Transcription Factors; D014212:Tretinoin; C000607071:RARA protein, human; C000607072:Rara protein, mouse; C494093:Stat5a protein, mouse; C082925:retinoic acid receptor beta; C507924:JAK2 protein, human; C507926:Jak2 protein, mouse