Polo-like kinase 1 (Plk1): An Unexpected Player in DNA Replication

Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA. .
Cell Division (Impact Factor: 3.53). 02/2012; 7(1):3. DOI: 10.1186/1747-1028-7-3
Source: PubMed


Regulation of cell cycle progression is important for the maintenance of genome integrity, and Polo-like kinases (Plks) have been identified as key regulators of this process. It is well established that Polo-like kinase 1 (Plk1) plays critical roles in mitosis but little is known about its functions at other stages of the cell cycle. Here we summarize the functions of Plk1 during DNA replication, focusing on the molecular events related to Origin Recognition Complex (ORC), the complex that is essential for the initiation of DNA replication. Within the context of Plk1 phosphorylation of Orc2, we also emphasize regulation of Orc2 in different organisms. This review is intended to provide some insight into how Plk1 coordinates DNA replication in S phase with chromosome segregation in mitosis, and orchestrates the cell cycle as a whole.

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Available from: X. Shawn Liu, Jul 29, 2015
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    • "This pattern is consistent with previous studies showing that p53 protein transcriptionally represses CDC20 at the mRNA level in different types of DNA damaged cells (Banerjee et al., 2009; Kidokoro et al., 2008). We also observed reduced expression of polo-like kinase 1 (PLK1), a critical regulator of cell cycle progression and checkpoint modulation in response to DNA damage (Bahassi, 2011; Song et al., 2012). The reduced levels of PLK1 in Vero cells treated with Mix 100 could merely reflect the observed cell cycle arrest at G1/S transition , because peak expression of PLK1 mRNA and protein occurs in M phase (Uchiumi et al., 1997). "
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    • "All these Plk1 activities are associated with its subcellular localization. In interphase (G 1 , S, G 2 ), Plk1 is involved in DNA replication and centrosome maturation [13] [14], in prophase to mitotic entry [15] [16], in prometaphase and metaphase, Plk1 might be involved in spindle assembly/formation and at telephase, it acts as a key regulator of cytokinesis [17]. Hence, downregulation of Plk1 activity promotes cell cycle arrest and apoptosis [18] [19]. "
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    • "Consequently, the phosphorylation of overexpressed Plk1 biosensor could mostly reflect the progressive accumulation of Plk1 kinase itself during S/G2 progression exhibiting a basal activity rather than its activation process during G2 to mitosis progression. Nevertheless, it should be noticed that the activation kinetics reported by the Plk1 biosensor agree with recent publications suggesting a role of Plk1 during DNA replication (reviewed in [36]). Further investigations will be required to determine precisely when and where Plk1 activation by Aurora-A is taking place during G2 phase progression. "
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