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Plk1 phosphorylation of Orc2 promotes DNA replication under conditions of stress

Bing Song1, X Shawn Liu, Korbin Davis

  • 1Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA.

Molecular and Cellular Biology
|September 28, 2011
PubMed

Insights

Polo-like kinase 1 (Plk1) facilitates DNA replication under stress by phosphorylating Orc2. This phosphorylation is crucial for maintaining genomic integrity during challenging S-phase conditions.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Genetics

Background:

  • Polo-like kinase 1 (Plk1) is essential for mitosis.
  • Plk1's role in S phase and DNA replication remains largely unexplored.

Purpose of the Study:

  • To investigate the function of Plk1 during S phase and DNA replication.
  • To identify Plk1 targets involved in DNA replication regulation.

Main Methods:

  • Cell culture and treatment with DNA replication inhibitors (UV, hydroxyurea, gemcitabine, aphidicolin).
  • Identification of Plk1 substrates using in vitro and in vivo assays.
  • Analysis of Orc2 phosphorylation mutants (S188A) in DNA replication and cell cycle progression.

Main Results:

  • Plk1 inhibition impairs DNA replication and slows S-phase progression.
  • Origin recognition complex 2 (Orc2) is a novel Plk1 substrate, phosphorylated at Ser188 (Orc2-S188).
  • Orc2-S188 phosphorylation is enhanced under replication stress and is critical for DNA synthesis, pre-replicative complex maintenance, and intra-S-phase checkpoint regulation.

Conclusions:

  • Plk1 plays a novel role in promoting DNA replication under stress conditions.
  • Orc2 phosphorylation by Plk1 is a key mechanism for maintaining genomic integrity during replication stress.

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