title: CK2 phosphorylation of C/EBPδ regulates its transcription factor activity.
abstract: Protein kinase CK2 plays an essential role in cell viability in lower and higher eukaryotes. As a global regulator it phosphorylates and thereby regulates a broad array of cellular targets including a large number of transcription factors. Here, we have identified the CCAAT/enhancer binding protein δ (C/EBPδ) as a new substrate for CK2. Using point mutants of C/EBPδ the major phosphorylation site for CK2 was mapped to serine 57, which is located within the transactivation domain of C/EBPδ. For proper functioning as a transcription factor C/EBPδ has to be translocated into the nucleus where it forms heterodimers with other members of the C/EBP family of proteins and ATF4. Here, we found that CK2 phosphorylation does neither influence the subcellular localization of C/EBPδ nor its interaction with C/EBPβ, but rather does CK2 phosphorylation modulate the transcriptional activity of C/EBPδ. Moreover, we found that CK2 bound to C/EBPδ, which might help to target CK2 to the transcriptional machinery where it can phosphorylate other transcription factors or co-activators.
authors: Medical Biochemistry and Molecular Biology, Saarland University, Building 44, D-66424 Homburg, Germany.
authors: Lisa
authors: L
authors: Schwind
authors: Medical Biochemistry and Molecular Biology, Saarland University, Building 44, D-66424 Homburg, Germany.
authors: Andreas D
authors: AD
authors: Zimmer
authors: Medical Biochemistry and Molecular Biology, Saarland University, Building 44, D-66424 Homburg, Germany.
authors: Claudia
authors: C
authors: Götz
authors: Medical Biochemistry and Molecular Biology, Saarland University, Building 44, D-66424 Homburg, Germany. Electronic address: Mathias.Montenarh@uks.eu.
authors: Mathias
authors: M
authors: Montenarh
mesh_terms: D000595:Amino Acid Sequence; D051743:CCAAT-Enhancer-Binding Protein-delta / Q000235:genetics / Q000378:metabolism*; D047390:Casein Kinase II / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D020134:Catalytic Domain; D017124:Conserved Sequence; D045325:HCT116 Cells; D006801:Humans; D008969:Molecular Sequence Data; D010766:Phosphorylation; D054730:Protein Interaction Domains and Motifs; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D059467:Transcriptome
chemical_list: D047428:Protein Kinase Inhibitors; D051743:CCAAT-Enhancer-Binding Protein-delta; D047390:Casein Kinase II
keywords: Phosphorylation; Protein kinase CK2; Protein–protein interaction; Transcription; Transcription factor