title: C/EBPα and DEK coordinately regulate myeloid differentiation.
abstract: The transcription factor C/EBPα is a critical mediator of myeloid differentiation and is often functionally impaired in acute myeloid leukemia. Recent studies have suggested that oncogenic FLT3 activity disrupts wild-type C/EBPα function via phosphorylation on serine 21 (S21). Despite the apparent role of pS21 as a negative regulator of C/EBPα transcription activity, the mechanism by which phosphorylation tips the balance between transcriptionally competent and inhibited forms remains unresolved. In the present study, we used immuno-affinity purification combined with quantitative mass spectrometry to delineate the proteins associated with C/EBPα on chromatin. We identified DEK, a protein with genetic links to leukemia, as a member of the C/EBPα complexes, and demonstrate that this association is disrupted by S21 phosphorylation. We confirmed that DEK is recruited specifically to chromatin with C/EBPα to enhance GCSFR3 promoter activation. In addition, we demonstrated that genetic depletion of DEK reduces the ability of C/EBPα to drive the expression of granulocytic target genes in vitro and disrupts G-CSF-mediated granulocytic differentiation of fresh human BM-derived CD34(+) cells. Our data suggest that C/EBPα and DEK coordinately activate myeloid gene expression and that S21 phosphorylation on wild-type C/EBPα mediates protein interactions that regulate the differentiation capacity of hematopoietic progenitors.
authors.affiliation: Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215-5450, USA.
authors.forename: Rositsa I
authors.initials: RI
authors.lastname: Koleva
authors.forename: Scott B
authors.initials: SB
authors.lastname: Ficarro
authors.forename: Hanna S
authors.initials: HS
authors.lastname: Radomska
authors.forename: Marlene J
authors.initials: MJ
authors.lastname: Carrasco-Alfonso
authors.forename: John A
authors.initials: JA
authors.lastname: Alberta
authors.forename: James T
authors.initials: JT
authors.lastname: Webber
authors.forename: C John
authors.initials: CJ
authors.lastname: Luckey
authors.forename: Guido
authors.initials: G
authors.lastname: Marcucci
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Tenen
authors.forename: Jarrod A
authors.initials: JA
authors.lastname: Marto
mesh_terms: D000906:Antibodies / Q000494:pharmacology; D022762:CCAAT-Enhancer-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D002478:Cells, Cultured; D002868:Chromosomal Proteins, Non-Histone / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D005786:Gene Expression Regulation / Q000187:drug effects; D055785:Gene Knockdown Techniques; D057809:HEK293 Cells; D006410:Hematopoiesis / Q000187:drug effects / Q000235:genetics; D006801:Humans; D020014:K562 Cells; D020930:MAP Kinase Kinase Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D022423:Myeloid Cells / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D015513:Oncogene Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D010766:Phosphorylation / Q000187:drug effects / Q000502:physiology; D000075223:Poly-ADP-Ribose Binding Proteins; D011485:Protein Binding / Q000187:drug effects; D047428:Protein Kinase Inhibitors / Q000494:pharmacology
chemical_list: D000906:Antibodies; D022762:CCAAT-Enhancer-Binding Proteins; C515848:CEBPA protein, human; D002868:Chromosomal Proteins, Non-Histone; C084738:DEK protein, human; D015513:Oncogene Proteins; D000075223:Poly-ADP-Ribose Binding Proteins; D047428:Protein Kinase Inhibitors; D020930:MAP Kinase Kinase Kinases