L2DTL/CDT2 and PCNA interact with p53 and regulate p53 polyubiquitination and protein stability through MDM2 and CUL4A/DDB1 complexes.
The CUL4-ROC1 E3 ligase complex regulates genome stability, replication and cell cycle progression. A novel WD40 domain-containing protein, L2DTL/CDT2 and PCNA were identified as proteins associated with CUL4/DDB1 complexes. Inactivation of CUL4A, L2DTL, PCNA, DDB1 or ROC1 induced p53 stabilization and growth arrest. L2DTL, PCNA and DDB1/CUL4A complexes were found to physically interact with p53 tumor suppressor and its regulator MDM2/HDM2. The isolated CUL4A complexes display potent and robust polyubiquitination activity towards p53 and this activity is dependent on L2DTL, PCNA, DDB1, ROC1 and MDM2/HDM2. We also found that the interaction between p53 and CUL4 complex is regulated by DNA damage. Our data further showed that MDM2/HDM2 is rapidly proteolyzed in response to UV irradiation and this process is regulated by CUL4/DDB1 and PCNA. Our studies demonstrate that PCNA, L2DTL and the DDB1-CUL4A complex play critical and differential roles in regulating the protein stability of p53 and MDM2/HDM2 in unstressed and stressed cells.
Banks
Damon
D
Department of Genetics, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
Wu
Min
M
Higa
Leigh Ann
LA
Gavrilova
Nadia
N
Quan
Junmin
J
Ye
Tao
T
Kobayashi
Ryuji
R
Sun
Hong
H
Zhang
Hui
H
D048868:Adaptor Proteins, Signal Transducing / Q000172:deficiency / Q000378:metabolism*; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D044842:Cullin Proteins / Q000302:isolation & purification / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000378:metabolism*; D005720:Gamma Rays; D006367:HeLa Cells; D006360:Heat-Shock Proteins / Q000172:deficiency / Q000378:metabolism*; D006801:Humans; D051379:Mice; D009687:Nuclear Proteins; D025821:Polyubiquitin / Q000378:metabolism*; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism*; D011485:Protein Binding / Q000528:radiation effects; D011499:Protein Processing, Post-Translational / Q000528:radiation effects; D051736:Proto-Oncogene Proteins c-mdm2 / Q000378:metabolism*; D013816:Thermodynamics; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D043743:Ubiquitin-Protein Ligase Complexes / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases; D014466:Ultraviolet Rays
D048868:Adaptor Proteins, Signal Transducing; C114234:CUL4A protein, human; D002352:Carrier Proteins; D044842:Cullin Proteins; C091435:DDB1 protein, human; D004268:DNA-Binding Proteins; C429530:DTL protein, human; D006360:Heat-Shock Proteins; D009687:Nuclear Proteins; D018809:Proliferating Cell Nuclear Antigen; C479529:RBX1 protein, human; D016159:Tumor Suppressor Protein p53; D025821:Polyubiquitin; D043743:Ubiquitin-Protein Ligase Complexes; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2; D044767:Ubiquitin-Protein Ligases