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A bipolar kinesin

A S Kashina1, R J Baskin, D G Cole

  • 1Section of Molecular and Cellular Biology, University of California, Davis 95616, USA.

Nature
|January 18, 1996
PubMed

Insights

KRP130, a kinesin motor protein, forms a unique bipolar structure. This structure, with motors at both ends, may be crucial for organizing microtubules during cell division.

Area of Science:

  • Cell Biology
  • Molecular Motors
  • Biophysics

Background:

  • Mitotic spindle function is critical for chromosome segregation during cell division.
  • Microtubule (MT)-motor proteins, particularly the BimC kinesin subfamily, are essential for bipolar spindle formation and function.
  • Understanding the structure and mechanism of these motors is key to comprehending mitosis.

Purpose of the Study:

  • To investigate the ultrastructure of KRP130, a homotetrameric BimC-related kinesin from Drosophila melanogaster.
  • To elucidate the potential role of KRP130's unique structure in microtubule organization within the mitotic spindle.

Main Methods:

  • Purification of KRP130 from Drosophila melanogaster embryos.
  • Ultrastructural analysis of the purified KRP130 protein complex.
  • Biochemical characterization of the kinesin motor properties.

Main Results:

  • KRP130 exhibits an unusual homotetrameric bipolar aggregate structure.
  • The motor domains of KRP130 are positioned at opposite ends of the aggregate, resembling a miniature myosin filament.
  • This bipolar 'minifilament' structure is novel among known MT motors.

Conclusions:

  • KRP130's bipolar structure suggests a mechanism for crosslinking and sliding microtubules.
  • This unique motor organization may play a significant role in establishing and maintaining the bipolar mitotic spindle.
  • Further research is needed to fully understand the functional implications of this novel motor architecture.

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