Retinoblastoma tumor suppressor protein signals through inhibition of cyclin-dependent kinase 2 activity to disrupt PCNA function in S phase

Zvjezdana Sever-Chroneos, Steven P. Angus, Anne F. Fribourg, Huajing Wan, Ivan Todorov, Karen E. Knudsen, Erik S. Knudsen

Research output: Contribution to journalArticle

46 Citations (Scopus)

Abstract

The retinoblastoma tumor suppressor protein (RB) is a negative regulator of the cell cycle that inhibits both G1 and S-phase progression. While RB-mediated G1 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.

Original languageEnglish (US)
Pages (from-to)4032-4045
Number of pages14
JournalMolecular and Cellular Biology
Volume21
Issue number12
DOIs
StatePublished - Jun 2001

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Cyclin-Dependent Kinase 2
Tumor Suppressor Proteins
Retinoblastoma Protein
Proliferating Cell Nuclear Antigen
S Phase
Chromatin
Cyclin A
DNA Replication
Down-Regulation
G1 Phase
DNA Damage
Cell Cycle
Alleles

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cell Biology

Cite this

Retinoblastoma tumor suppressor protein signals through inhibition of cyclin-dependent kinase 2 activity to disrupt PCNA function in S phase. / Sever-Chroneos, Zvjezdana; Angus, Steven P.; Fribourg, Anne F.; Wan, Huajing; Todorov, Ivan; Knudsen, Karen E.; Knudsen, Erik S.

In: Molecular and Cellular Biology, Vol. 21, No. 12, 06.2001, p. 4032-4045.

Research output: Contribution to journalArticle

Sever-Chroneos, Zvjezdana ; Angus, Steven P. ; Fribourg, Anne F. ; Wan, Huajing ; Todorov, Ivan ; Knudsen, Karen E. ; Knudsen, Erik S. / Retinoblastoma tumor suppressor protein signals through inhibition of cyclin-dependent kinase 2 activity to disrupt PCNA function in S phase. In: Molecular and Cellular Biology. 2001 ; Vol. 21, No. 12. pp. 4032-4045.
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