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Retinoblastoma tumor suppressor protein signals through inhibition of cyclin-dependent kinase 2 activity to disrupt PCNA function in S phase.
- Source :
-
Molecular and cellular biology [Mol Cell Biol] 2001 Jun; Vol. 21 (12), pp. 4032-45. - Publication Year :
- 2001
-
Abstract
- The retinoblastoma tumor suppressor protein (RB) is a negative regulator of the cell cycle that inhibits both G(1) and S-phase progression. While RB-mediated G(1) inhibition has been extensively studied, the mechanism utilized for S-phase inhibition is unknown. To delineate the mechanism through which RB inhibits DNA replication, we generated cells which inducibly express a constitutively active allele of RB (PSM-RB). We show that RB-mediated S-phase inhibition does not inhibit the chromatin binding function of MCM2 or RPA, suggesting that RB does not regulate the prereplication complex or disrupt early initiation events. However, activation of RB in S-phase cells disrupts the chromatin tethering of PCNA, a requisite component of the DNA replication machinery. The action of RB was S phase specific and did not inhibit the DNA damage-mediated association of PCNA with chromatin. We also show that RB-mediated PCNA inhibition was dependent on downregulation of CDK2 activity, which was achieved through the downregulation of cyclin A. Importantly, restoration of cyclin-dependent kinase 2 (CDK2)-cyclin A and thus PCNA activity partially restored S-phase progression in the presence of active RB. Therefore, the data presented identify RB-mediated regulation of PCNA activity via CDK2 attenuation as a mechanism through which RB regulates S-phase progression. Together, these findings identify a novel pathway of RB-mediated replication inhibition.
- Subjects :
- Animals
Base Sequence
Cell Line
Chromatin metabolism
Cyclin A metabolism
Cyclin-Dependent Kinase 2
DNA Primers genetics
DNA Replication
DNA-Binding Proteins metabolism
Rats
Replication Protein A
Retinoblastoma Protein genetics
Signal Transduction
CDC2-CDC28 Kinases
Cyclin-Dependent Kinases antagonists & inhibitors
Proliferating Cell Nuclear Antigen metabolism
Protein Serine-Threonine Kinases antagonists & inhibitors
Retinoblastoma Protein metabolism
S Phase physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0270-7306
- Volume :
- 21
- Issue :
- 12
- Database :
- MEDLINE
- Journal :
- Molecular and cellular biology
- Publication Type :
- Academic Journal
- Accession number :
- 11359910
- Full Text :
- https://doi.org/10.1128/MCB.21.12.4032-4045.2001