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Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay
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Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay

Published on: May 3, 2018

Phosphorylation of right open reading frame 2 (Rio2) protein kinase by polo-like kinase 1 regulates mitotic

Ting Liu1, Min Deng, Junhui Li

  • 1Center for Molecular Immunology, Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.

The Journal of Biological Chemistry
|September 2, 2011
PubMed

Insights

Polo-like kinase 1 (Plk1) phosphorylates the atypical protein kinase Rio2, regulating its function in mitotic progression. This Plk1-mediated phosphorylation of Rio2 is crucial for controlling the metaphase-anaphase transition during cell division.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Polo-like kinase 1 (Plk1) is a key regulator of mitosis, phosphorylating numerous substrates.
  • The atypical protein kinase Rio2's role in mitosis requires further elucidation.

Purpose of the Study:

  • To identify novel substrates of Plk1.
  • To investigate the role of Rio2 phosphorylation by Plk1 in mitotic progression.

Main Methods:

  • Phosphorylation site mapping of Rio2 by Plk1.
  • Overexpression and knockdown studies of Rio2.
  • Analysis of phospho-mimicking and nonphosphorylatable Rio2 mutants.
  • Time-lapse microscopy to observe mitotic progression.

Main Results:

  • Rio2 is identified as a novel substrate of Plk1, phosphorylated at Ser-335, Ser-380, and Ser-548.
  • Altered Rio2 levels affect mitotic progression; overexpression prolongs mitotic exit, while knockdown accelerates it.
  • Phosphorylation status of Rio2 correlates with its function, with phospho-mimicking mutants behaving similarly to wild-type Rio2.
  • Plk1-mediated phosphorylation of Rio2 specifically slows the metaphase-anaphase transition.

Conclusions:

  • Plk1-mediated phosphorylation of Rio2 is a critical regulatory mechanism.
  • Rio2 phosphorylation by Plk1 is essential for controlling the metaphase-anaphase transition.
  • This interaction highlights a novel pathway in mitotic regulation.

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