Repression of GCN5 histone acetyltransferase activity via bromodomain-mediated binding and phosphorylation by the Ku-DNA-dependent protein kinase complex.
GCN5, a putative transcriptional adapter in humans and yeast, possesses histone acetyltransferase (HAT) activity which has been linked to GCN5's role in transcriptional activation in yeast. In this report, we demonstrate a functional interaction between human GCN5 (hGCN5) and the DNA-dependent protein kinase (DNA-PK) holoenzyme. Yeast two-hybrid screening detected an interaction between the bromodomain of hGCN5 and the p70 subunit of the human Ku heterodimer (p70-p80), which is the DNA-binding component of DNA-PK. Interaction between intact hGCN5 and Ku70 was shown biochemically using recombinant proteins and by coimmunoprecipitation of endogenous proteins following chromatography of HeLa nuclear extracts. We demonstrate that the catalytic subunit of DNA-PK phosphorylates hGCN5 both in vivo and in vitro and, moreover, that the phosphorylation inhibits the HAT activity of hGCN5. These findings suggest a possible regulatory mechanism of HAT activity.
Barlev
N A
NA
The Wistar Institute, Philadelphia, Pennsylvania 19104, USA.
Poltoratsky
V
V
Owen-Hughes
T
T
Ying
C
C
Liu
L
L
Workman
J L
JL
Berger
S L
SL
D000123:Acetyltransferases / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D034961:Antigens, Nuclear; D001665:Binding Sites; D002458:Cell Fractionation; D003067:Coenzymes / Q000378:metabolism*; D004265:DNA Helicases; D051747:DNA-Activated Protein Kinase; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D051548:Histone Acetyltransferases; D006801:Humans; D000072200:Ku Autoantigen; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D014407:Tumor Cells, Cultured; D000099224:p300-CBP-Associated Factor
D000123:Acetyltransferases; D034961:Antigens, Nuclear; D003067:Coenzymes; D004265:DNA Helicases; D051747:DNA-Activated Protein Kinase; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D051548:Histone Acetyltransferases; D000072200:Ku Autoantigen; D009687:Nuclear Proteins; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; C081647:high affinity DNA-binding factor, S cerevisiae; C501392:GCN5 protein, S cerevisiae; D000099224:p300-CBP-Associated Factor; C497263:PRKDC protein, human; C106893:XRCC5 protein, human; C000606509:Xrcc6 protein, human