Human CDK2 Inhibition Modifies the Dynamics of Chromatin-Bound Minichromosome Maintenance Complex and Replication Protein A

Zhu, Yonghong; Ishimi, Yukio; Tanudji, Marcel; Lees, Emma

doi:10.4161/cc.4.9.1975

Cited by 21 publications

(19 citation statements)

References 43 publications

(66 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Even though geminin is not degraded after DNA damage (Higa et al, 2003 and our unpublished observations), the persistence of geminin during a checkpoint response is not sufficient to block substantial preRC reassembly. This assertion is supported by previous findings that direct inhibition of Cdk activity during G2, either pharmacologically or genetically, permits reloading of MCM proteins onto chromatin even in the presence of geminin (Bates et al, 1998;Ballabeni et al, 2004;Zhu et al, 2005). Thus, there is a risk of genome instability if preRCs are permitted to assemble while Cdk activity is inhibited.…”

Section: Discussionsupporting

confidence: 69%

Cdc6 Stability Is Regulated by the Huwe1 Ubiquitin Ligase after DNA Damage

Hall

Kow

Nevis

et al. 2007

MBoC

130

140

View full text Add to dashboard Cite

The Cdc6 protein is an essential component of pre-replication complexes (preRCs), which assemble at origins of DNA replication during the G1 phase of the cell cycle. Previous studies have demonstrated that, in response to ionizing radiation, Cdc6 is ubiquitinated by the anaphase promoting complex (APC Cdh1 ) in a p53-dependent manner. We find, however, that DNA damage caused by UV irradiation or DNA alkylation by methyl methane sulfonate (MMS) induces Cdc6 degradation independently of p53. We further demonstrate that Cdc6 degradation after these forms of DNA damage is also independent of cell cycle phase, Cdc6 phosphorylation of the known Cdk target residues, or the Cul4/DDB1 and APC Cdh1 ubiquitin E3 ligases. Instead Cdc6 directly binds a HECT-family ubiquitin E3 ligase, Huwe1 (also known as Mule, UreB1, ARF-BP1, Lasu1, and HectH9), and Huwe1 polyubiquitinates Cdc6 in vitro. Degradation of Cdc6 in UV-irradiated cells or in cells treated with MMS requires Huwe1 and is associated with release of Cdc6 from chromatin. Furthermore, yeast cells lacking the Huwe1 ortholog, Tom1, have a similar defect in Cdc6 degradation. Together, these findings demonstrate an important and conserved role for Huwe1 in regulating Cdc6 abundance after DNA damage. INTRODUCTIONDuplication of large mammalian genomes requires that DNA replication initiate at thousands of chromosomal origins. In order for an origin to be competent for replication, it must first be bound by a multiprotein complex, the prereplication complex (preRC). PreRCs are constructed in a stepwise process through the chromatin binding of the origin recognition complex (ORC), which then recruits both the Cdc6 ATPase and Cdt1, two proteins that are required for the stable loading of the minichromosome maintenance complex (MCM). The Cdc6 and Cdt1-dependent loading of MCM complexes at origins licenses them for replication during the G1 phase of the cell cycle. Sufficient preRCs must be assembled during G1 to promote complete replication, but new preRCs must not assemble after S phase begins because relicensing of previously fired origins leads to rereplication and genome instability (Vaziri et al., 2003;Melixetian et al., 2004;Zhu et al., 2004;Archambault et al., 2005). For these reasons, preRC assembly is one of the most highly regulated events in the control of DNA replication. Cells restrict preRC assembly to the G1 period through a combination of overlapping mechanisms that regulate individual preRC components (reviewed in Bell and Dutta, 2002;Blow and Hodgson, 2002;Nishitani and Lygerou, 2002;Diffley, 2004;Machida et al., 2005;Fujita, 2006).Cdc6 is not only an essential factor for preRC construction, but it has also been implicated in the activation of the cell cycle checkpoint that prevents entry into mitosis while DNA replication is incomplete (Clay-Farrace et al., 2003;Oehlmann et al., 2004;Lau et al., 2006). These observations suggest that Cdc6 functions not only during G1, but also in later cell cycle stages. Moreover, Cdc6 plays a role in setting the threshold for...

show abstract

Section: Discussionsupporting

confidence: 69%

Cdc6 Stability Is Regulated by the Huwe1 Ubiquitin Ligase after DNA Damage

Hall

Kow

Nevis

et al. 2007

MBoC

130

140

View full text Add to dashboard Cite

show abstract

“…For example, it has been shown that both CDK2 and CDK1 phosphorylate several minichromosome maintenance (MCM) factors, which are core components of a helicase complex and in their hypophosphorylated state help to unwind the DNA and establish a replication fork [36]. Loss of CDK2 function in G1 phase of the cell cycle results in reduced and suboptimal MCM4 phosphorylation in human ovarian cancer cell lines, thus, causing increased loading of the MCM complex onto chromatin and activation of checkpoint response [37]. Our proteomic analyses suggest that CDK2 interacts directly with several MCM core factors, including MCM2, MCM6, MCM7 as well as other helicases such as DHX9, SMARCA5, and replication factors including proliferating cell nuclear antigen.…”

Section: Discussionmentioning

confidence: 99%

An Important Role for CDK2 in G1 to S Checkpoint Activation and DNA Damage Response in Human Embryonic Stem Cells

et al. 2011

View full text Add to dashboard Cite

A precise understanding of mechanisms used by human embryonic stem cells (hESCs) to maintain genomic integrity is very important for their potential clinical applications. The G1 checkpoint serves to protect genomic integrity and prevents cells with damaged DNA from entering S-phase. Previously, we have shown that downregulation of cyclindependent kinase 2 (CDK2) in hESC causes G1 arrest, loss of pluripotency, upregulation of cell cycle inhibitors p21 and p27 and differentiation toward extraembryonic lineages. In this study, we investigate in detail the role of CDK2 in cellular processes, which are crucial to the maintenance of genomic stability in hESC such as G1 checkpoint activation, DNA repair, and apoptosis. Our results suggest that downregulation of CDK2 triggers the G1 checkpoint through the activation of the ATM-CHK2-p53-p21 pathway. Downregulation of CDK2 is able to induce sustained DNA damage and to elicit the DNA damage response (DDR) as evidenced by the formation of distinct c-H2.AX and RAD52-BRCA1 foci in hESC nuclei. CDK2 downregulation causes high apoptosis at the early time points; however, this is gradually decreased overtime as the DDR is initiated. Our mass spectrometry analysis suggest that CDK2 does interact with a large number of proteins that are involved in key cellular processes such as DNA replication, cell cycle progression, DNA repair, chromatin modeling, thus, suggesting a crucial role for CDK2 in orchestrating a fine balance between cellular proliferation, cell death, and DNA repair in hESC. STEM CELLS 2011;29:651-659 Disclosure of potential conflicts of interest is found at the end of this article.

show abstract

“…CDK2 also phosphorylates minichromosome maintenance (MCM) proteins during DNA replication, thus blocking continued replication origin firing. CDK2 inhibition, therefore, causes over-replication, resulting in the formation of DSBs and single stranded DNA intermediates that activate ATM and ATR, eliciting an intra-S-phase checkpoint (38, 39). Most recently, chemical genetics experiments have revealed a non-redundant requirement for CDK2 activity in the DDR and a specific target of CDK2 (Nijmegen Breakage Syndrome gene product 1, Nbs-1) within the DNA repair machinery (40).…”

Section: New Insights Into Cdk Functions and Mechanisms Of Action mentioning

confidence: 99%

Cyclin-dependent kinase inhibitor therapy for hematologic malignancies

Bose¹,

Simmons²,

Grant³

2013

Expert Opinion on Investigational Drugs

131

View full text Add to dashboard Cite

INTRODUCTION Cyclin-dependent kinases (CDKs) regulate cell cycle progression. Certain CDKs (e.g., CDK7, CDK9) also control cellular transcription. Consequently, CDKs represent attractive targets for anti-cancer drug development, as their aberrant expression is common in diverse malignancies, and CDK inhibition can trigger apoptosis. CDK inhibition may be particularly successful in hematologic malignancies, which are more sensitive to inhibition of cell cycling and apoptosis induction. AREAS COVERED A number of CDK inhibitors, ranging from pan-CDK inhibitors such as flavopiridol (alvocidib) to highly selective inhibitors of specific CDKs (e.g., CDK4/6), such as PD0332991, that are currently in various phases of development, are profiled in this review. Flavopiridol induces cell cycle arrest, and globally represses transcription via CDK9 inhibition. The latter may represent its major mechanism of action via down-regulation of multiple short-lived proteins. In early phase trials, flavopiridol has shown encouraging efficacy across a wide spectrum of hematologic malignancies. Early results with dinaciclib and PD0332991 also appear promising. EXPERT OPINION In general, the anti-tumor efficacy of CDK inhibitor monotherapy is modest, and rational combinations are being explored, including those involving other targeted agents. While selective CDK4/6 inhibition might be effective against certain malignancies, broad spectrum CDK inhibition will likely be required for most cancers.

show abstract

Human CDK2 Inhibition Modifies the Dynamics of Chromatin-Bound Minichromosome Maintenance Complex and Replication Protein A

Cited by 21 publications

References 43 publications

Cdc6 Stability Is Regulated by the Huwe1 Ubiquitin Ligase after DNA Damage

Cdc6 Stability Is Regulated by the Huwe1 Ubiquitin Ligase after DNA Damage

An Important Role for CDK2 in G1 to S Checkpoint Activation and DNA Damage Response in Human Embryonic Stem Cells

Cyclin-dependent kinase inhibitor therapy for hematologic malignancies

Contact Info

Product

Resources

About