Intra-S-phase checkpoint activation by direct CDK2 inhibition

Yonghong Zhu; Carmen Alvarez; Ronald Doll; Hirokazu Kurata; Xiao Min Schebye; David Parry; Emma Lees

doi:10.1128/MCB.24.14.6268-6277.2004

Intra-S-phase checkpoint activation by direct CDK2 inhibition

Mol Cell Biol. 2004 Jul;24(14):6268-77. doi: 10.1128/MCB.24.14.6268-6277.2004.

Authors

Yonghong Zhu¹, Carmen Alvarez, Ronald Doll, Hirokazu Kurata, Xiao Min Schebye, David Parry, Emma Lees

Affiliation

¹ Molecular Oncology Laboratory, Department of Discovery Research, DNAX Research, Inc., Palo Alto, CA 94304, USA. [email protected]

Abstract

To ensure proper progression through a cell cycle, checkpoints have evolved to play a surveillance role in maintaining genomic integrity. In this study, we demonstrate that loss of CDK2 activity activates an intra-S-phase checkpoint. CDK2 inhibition triggers a p53-p21 response via ATM- and ATR-dependent p53 phosphorylation at serine 15. Phosphorylation of other ATM and ATR downstream substrates, such as H2AX, NBS1, CHK1, and CHK2 is also increased. We show that during S phase when CDK2 activity is inhibited, there is an unexpected loading of the minichromosome maintenance complex onto chromatin. In addition, there is an increased number of cells with more than 4N DNA content, detected in the absence of p53, suggesting that rereplication can occur as a result of CDK2 disruption. Our findings identify an important role for CDK2 in the maintenance of genomic stability, acting via an ATM- and ATR-dependent pathway.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Ataxia Telangiectasia Mutated Proteins
CDC2-CDC28 Kinases / antagonists & inhibitors*
CDC2-CDC28 Kinases / metabolism*
Caffeine / metabolism
Cell Cycle / physiology*
Cell Cycle Proteins / metabolism*
Cell Line, Tumor
Chromatin / metabolism
Cyclin-Dependent Kinase 2
Cyclin-Dependent Kinase Inhibitor p21
Cyclins / metabolism
DNA Replication
DNA-Binding Proteins
Enzyme Inhibitors / metabolism
Humans
Phosphorylation
Protein Serine-Threonine Kinases / metabolism*
RNA, Small Interfering / metabolism
Serine / metabolism
Tumor Suppressor Protein p53 / metabolism
Tumor Suppressor Proteins

Substances

CDKN1A protein, human
Cell Cycle Proteins
Chromatin
Cyclin-Dependent Kinase Inhibitor p21
Cyclins
DNA-Binding Proteins
Enzyme Inhibitors
RNA, Small Interfering
Tumor Suppressor Protein p53
Tumor Suppressor Proteins
Caffeine
Serine
ATM protein, human
ATR protein, human
Ataxia Telangiectasia Mutated Proteins
Protein Serine-Threonine Kinases
CDC2-CDC28 Kinases
CDK2 protein, human
Cyclin-Dependent Kinase 2