Phosphorylation of HDM2 by Akt.
The HDM2 protein is a key regulator of the tumour suppressor, p53. Control of HDM2 function is critical for normal cell proliferation and stress responses, and it is becoming evident that multiple modifications of HDM2 can regulate its function within cells. In this study we show that HDM2 associated with the serine-threonine kinase, Akt, in response to growth factor stimulation of human primary cells. This association was concurrent with phosphorylation of Akt (at Ser 473), and resulted in elevated expression of HDM2 and enhanced nuclear localization. However, analysis of HDM2 proteins mutated at the consensus Akt recognition sites at serines 166 and 186 indicated that modification at these residues was not sufficient for the increased expression of the protein, which was blocked by the PI3 kinase inhibitor LY294002. Tryptic peptide and mutational analyses revealed evidence for an Akt phosphorylation site in HDM2 additional to the two consensus sites.
Ashcroft
Margaret
M
CRC, Centre for Cancer Therapeutics, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK. ashcroft@icr.ac.uk
Ludwig
Robert L
RL
Woods
Douglas B
DB
Copeland
Terry D
TD
Weber
H Oliver
HO
MacRae
Elizabeth J
EJ
Vousden
Karen H
KH
D000595:Amino Acid Sequence; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D016384:Consensus Sequence; D004789:Enzyme Activation; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D009687:Nuclear Proteins; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D051736:Proto-Oncogene Proteins c-mdm2; D014162:Transfection
D009687:Nuclear Proteins; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010768:Phosphoserine; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D051736:Proto-Oncogene Proteins c-mdm2; C497206:MDM2 protein, human; C494918:AKT1 protein, human