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The phosphatase Cdc14 triggers mitotic exit by reversal of Cdk-dependent phosphorylation

R Visintin1, K Craig, E S Hwang

  • 1Whitehead Institute for Biomedical Research, Cambridge Center, Massachusetts 02142, USA.

Molecular Cell
|January 14, 1999
PubMed

Insights

The Cdc14 phosphatase triggers mitotic exit by inactivating mitotic cyclin-dependent kinases (CDKs) through three parallel pathways. This coordinated action ensures the timely and precise collapse of CDK activity, facilitating cell cycle progression.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Mitotic exit, crucial for cell division, necessitates the inactivation of mitotic cyclin-dependent kinases (CDKs).
  • The precise molecular mechanisms governing mitotic CDK inactivation remain incompletely understood.

Purpose of the Study:

  • To elucidate the role of the Cdc14 phosphatase in triggering mitotic exit.
  • To identify the specific mechanisms by which Cdc14 inhibits CDK activity.

Main Methods:

  • Investigated the function of Cdc14 phosphatase in regulating mitotic CDK activity.
  • Analyzed the dephosphorylation of key substrates including Sic1, Swi5, and Cdh1/Hct1.

Main Results:

  • Demonstrated that Cdc14 triggers mitotic exit via three parallel pathways that inhibit CDK activity.
  • Showed Cdc14 dephosphorylates Sic1 (a CDK inhibitor) and Swi5 (a transcription factor for SIC1).
  • Indicated Cdc14 induces mitotic cyclin degradation, likely by dephosphorylating Cdh1/Hct1 (activator of cyclin degradation).

Conclusions:

  • Cdc14 phosphatase is a central regulator of mitotic exit, acting through multiple coordinated mechanisms.
  • Feedback loops between these pathways likely ensure a rapid and complete inactivation of mitotic CDK activity.
  • This coordinated regulation is essential for the precise timing of cell cycle progression out of mitosis.

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