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Kinesin-14 HSET and KlpA are non-processive microtubule motors with load-dependent power strokes

Xinglei Liu1, Lu Rao1, Weihong Qiu2

  • 1Department of Biochemistry and Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, USA.

Nature Communications
|August 2, 2024
PubMed

Insights

Kinesin-14 motors like HSET and KlpA are crucial for cell division. These motors generate force individually but cooperate in teams to enhance microtubule (MT) sliding and ensure accurate chromosome segregation.

Area of Science:

  • Cell Biology
  • Molecular Motors
  • Biophysics

Background:

  • Accurate chromosome segregation during cell division is essential and relies on microtubule (MT)-based motor proteins within the mitotic spindle.
  • Kinesin-14 motors are vital for spindle assembly and maintenance, crosslinking antiparallel MTs and anchoring MT minus ends at spindle poles.

Purpose of the Study:

  • To investigate the force generation and motility of Kinesin-14 motors, specifically HSET and KlpA.
  • To quantitatively elucidate the structure-function relationship of Kinesin-14 motors.

Main Methods:

  • Investigated force generation and motility of HSET and KlpA.
  • Measured single motor power strokes and forces.
  • Analyzed cooperative behavior of multiple motors.

Main Results:

  • HSET and KlpA were found to be non-processive motors, exhibiting single, load-dependent power strokes per MT encounter.
  • Estimated load-free power strokes were approximately 30 nm for HSET and 35 nm for KlpA.
  • Individual homodimeric motors generated forces of ~0.5 pN, while cooperative action in teams generated forces of 1 pN or more, leading to increased MT-sliding velocities.

Conclusions:

  • Cooperative activity among Kinesin-14 motors significantly enhances their force generation and MT-sliding velocity.
  • These findings underscore the importance of cooperative motor behavior for essential cellular functions like chromosome segregation.

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