Phosphorylation by protein kinase CK2 changes the DNA binding properties of the human chromatin protein DEK.
We have examined the posttranslational modification of the human chromatin protein DEK and found that DEK is phosphorylated by the protein kinase CK2 in vitro and in vivo. Phosphorylation sites were mapped by quadrupole ion trap mass spectrometry and found to be clustered in the C-terminal region of the DEK protein. Phosphorylation fluctuates during the cell cycle with a moderate peak during G(1) phase. Filter binding assays, as well as Southwestern analysis, demonstrate that phosphorylation weakens the binding of DEK to DNA. In vivo, however, phosphorylated DEK remains on chromatin. We present evidence that phosphorylated DEK is tethered to chromatin throughout the cell cycle by the un- or underphosphorylated form of DEK.
Kappes
Ferdinand
F
Department of Biology, University of Konstanz, Germany. Ferdinand.Kappes@gmx.de
Damoc
Catalina
C
Knippers
Rolf
R
Przybylski
Michael
M
Pinna
Lorenzo A
LA
Gruss
Claudia
C
D000595:Amino Acid Sequence; D001665:Binding Sites; D047390:Casein Kinase II; D002453:Cell Cycle; D002843:Chromatin / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D013058:Mass Spectrometry; D015513:Oncogene Proteins / Q000378:metabolism*; D010766:Phosphorylation; D000075223:Poly-ADP-Ribose Binding Proteins; D011499:Protein Processing, Post-Translational; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D016192:Resting Phase, Cell Cycle
D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; C084738:DEK protein, human; D015513:Oncogene Proteins; D000075223:Poly-ADP-Ribose Binding Proteins; D004247:DNA; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases