HDM2 negatively affects the Chk2-mediated phosphorylation of p53.
By GST pull downs and co-immunoprecipitation analyses we found that recombinant Chk2 and HDM2 can form stable complexes in vitro. Chk2/HDM2 complexes were also detected in transfected Cos-1 cells over-expressing both proteins. Furthermore, we show that HDM2, as would be expected, severely affects the Chk2-catalyzed phosphorylation of p53. HDM2 itself is only slightly phosphorylated by Chk2. However, whereas HDM2 inhibits the Chk2-catalyzed p53 phosphorylation, HDM2 phosphorylation by Chk2 doubles in the presence of p53. The significance of the HDM2 phosphorylation is unknown, but it is possible that it might influence the stability of the HDM2/p53 complex.
Bjørling-Poulsen
Marina
M
Institut for Biokemi og Molekylaer Biologi, Syddansk Universitet, Odense, Denmark.
Meek
David
D
Issinger
Olaf-Georg
OG
D000818:Animals; D015153:Blotting, Western; D019556:COS Cells; D002384:Catalysis; D064447:Checkpoint Kinase 2; D002522:Chlorocebus aethiops; D015870:Gene Expression; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D009687:Nuclear Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D010766:Phosphorylation; D011233:Precipitin Tests; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D051736:Proto-Oncogene Proteins c-mdm2; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D011994:Recombinant Proteins; D016159:Tumor Suppressor Protein p53; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2; D005982:Glutathione Transferase; D064447:Checkpoint Kinase 2; C578634:CHEK2 protein, human; D017346:Protein Serine-Threonine Kinases