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Slk19-dependent mid-anaphase pause in kinesin-5-mutated cells

Natalia Movshovich1, Vladimir Fridman, Adina Gerson-Gurwitz

  • 1Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel.

Journal of Cell Science
|July 17, 2008
PubMed

Insights

Mutations in kinesin-5 motor proteins in yeast cells disrupt anaphase spindle elongation, causing a mid-anaphase pause. This pause, dependent on Slk19, may ensure proper DNA segregation.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Genetics

Background:

  • Kinesin-5 motor proteins are crucial for spindle assembly and function.
  • Anaphase spindle elongation is a critical process for chromosome segregation.
  • The FEAR pathway regulates early-anaphase events, including Cdc14 phosphatase activation.

Purpose of the Study:

  • To investigate the role of kinesin-5 motor proteins (Cin8 and Kip1) in anaphase spindle elongation in Saccharomyces cerevisiae.
  • To determine the impact of specific kinesin-5 mutations on spindle dynamics and midzone organization.
  • To explore the involvement of FEAR pathway components and the pre-anaphase checkpoint in regulating spindle elongation defects.

Main Methods:

  • Yeast genetics: construction of kip1 deletion and expression of Cin8 motor-domain mutants (Cin8-F467A, Cin8-R196K).
  • Microscopy to observe anaphase spindle elongation and midzone structure.
  • Genetic manipulation of FEAR pathway components (SLK19, SPO12) and Cdc20 to assess their effects.

Main Results:

  • Kinesin-5 mutations, particularly in kip1 Delta cin8-F467A cells, led to interrupted spindle elongation and a mid-anaphase pause.
  • Mutant cells exhibited asymmetric midzone location and enlarged midzone size, indicating impaired organization.
  • Deletion of SLK19, but not SPO12, abolished the mid-anaphase pause, induced premature anaphase onset, and caused DNA division defects.
  • Overexpression of Cdc20 also eliminated the pause but resulted in DNA deformation.

Conclusions:

  • Proper kinesin-5 function and midzone organization are essential for continuous anaphase spindle elongation.
  • A Slk19-dependent mid-anaphase pause, potentially triggered by pre-anaphase checkpoint activation in kinesin-5 mutants, may be vital for accurate DNA segregation.

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