Association with Cdc2 and inhibition of Cdc2/Cyclin B1 kinase activity by the p53-regulated protein Gadd45.
Recently Gadd45, a p53-regulated stress protein, has been implicated in the activation of a G2/M checkpoint after damage by UV radiation and alkylating agents. While inhibitory phosphorylation of Cdc2 and suppression of cyclin B1 levels are known to be involved in G2 delays after genotoxic stress, Gadd45 has now been found to directly inhibit the activity of Cdc2/Cyclin B1 complex, while it had no appreciable effect on Cdk2/ Cyclin E activity even at very high levels of Gadd45. In contrast, p21CiP1/Waf1 is an universal cdk/cyclin inhibitor and inhibited both of the cyclin complexes tested here. Gadd45 was also able to physically interact with Cdc2, but not Cyclin B1. Addition of Gadd45 to immunoprecipitated Cdc2/Cyclin B1 in vitro led to a dissociation of this complex, and thus may represent a new checkpoint mechanism whereby Cdc2/Cyclin B1 can be inhibited. With the use of an antisense approach, reduced Gadd45 expression attenuated the suppression of Cdc2/Cyclin B1 activity in UV-irradiated human cells. Taken together, these results implicate Gadd45 in the control of G2/M cell cycle progression after certain stresses.
Zhan
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Laboratory of Biological Chemistry, Division of Basic Science, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
Antinore
M J
MJ
Wang
X W
XW
Carrier
F
F
Smith
M L
ML
Harris
C C
CC
Fornace
A J
AJ
D000911:Antibodies, Monoclonal / Q000737:chemistry; D016203:CDC2 Protein Kinase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D002277:Carcinoma / Q000235:genetics / Q000532:radiotherapy; D018797:Cell Cycle Proteins; D003110:Colonic Neoplasms / Q000235:genetics / Q000532:radiotherapy; D019926:Cyclin B / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism*; D056744:Cyclin B1; D019927:Cyclin E / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes; D016259:Genes, myc; D006657:Histones / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D056490:Nucleosome Assembly Protein 1; D011233:Precipitin Tests; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D016372:RNA, Antisense / Q000494:pharmacology; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D019311:Staurosporine / Q000494:pharmacology; D014162:Transfection; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D014466:Ultraviolet Rays; D000097642:GADD45 Proteins
D000911:Antibodies, Monoclonal; D016203:CDC2 Protein Kinase; D018797:Cell Cycle Proteins; D019926:Cyclin B; D056744:Cyclin B1; D019927:Cyclin E; D004791:Enzyme Inhibitors; D000939:Epitopes; D006657:Histones; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D056490:Nucleosome Assembly Protein 1; D011506:Proteins; D016372:RNA, Antisense; D011994:Recombinant Proteins; D019311:Staurosporine; D016159:Tumor Suppressor Protein p53; D000097642:GADD45 Proteins; C534699:CCNB1 protein, human; C533557:NAP1L1 protein, human