Searching across hundreds of databases

Our searching services are busy right now. Your search will reload in five seconds.

Forgot Password

If you have forgotten your password you can enter your email here and get a temporary password sent to your email.

Compression regulates mitotic spindle length by a mechanochemical switch at the poles.

Current biology : CB | Jul 14, 2009

BACKGROUND: Although the molecules involved in mitosis are becoming better characterized, we still lack an understanding of the emergent mechanical properties of the mitotic spindle. For example, we cannot explain how spindle length is determined. To gain insight into how forces are generated and responded to in the spindle, we developed a method to apply controlled mechanical compression to metaphase mitotic spindles in living mammalian cells while monitoring microtubules and kinetochores by fluorescence microscopy. RESULTS: Compression caused reversible spindle widening and lengthening to a new steady state. Widening was a passive mechanical response, and lengthening was an active mechanochemical process requiring microtubule polymerization but not kinesin-5 activity. Spindle morphology during lengthening and drug perturbations suggested that kinetochore fibers are pushed outward by pole-directed forces generated within the spindle. Lengthening of kinetochore fibers occurred by inhibition of microtubule depolymerization at poles, with no change in sliding velocity, interkinetochore stretching, or kinetochore dynamics. CONCLUSIONS: We propose that spindle length is controlled by a mechanochemical switch at the poles that regulates the depolymerization rate of kinetochore fibers in response to compression and discuss models for how this switch is controlled. Poleward force appears to be exerted along kinetochore fibers by some mechanism other than kinesin-5 activity, and we speculate that it may arise from polymerization pressure from growing plus ends of interpolar microtubules whose minus ends are anchored in the fiber. These insights provide a framework for conceptualizing mechanical integration within the spindle.

Pubmed ID: 19540117 RIS Download

Mesh terms: Animals | Cell Division | Centrosome | Kinetochores | Mechanotransduction, Cellular | Microtubules | Potoroidae | Recombinant Fusion Proteins | Spindle Apparatus | Stress, Mechanical | Tubulin

Research resources used in this publication

None found

Research tools detected in this publication

None found

Data used in this publication

None found

Associated grants

  • Agency: NIGMS NIH HHS, Id: GM039565
  • Agency: NIGMS NIH HHS, Id: P50 GM068763
  • Agency: NIGMS NIH HHS, Id: R01 GM039565-22
  • Agency: NIGMS NIH HHS, Id: P50 GM068763-060010
  • Agency: NIGMS NIH HHS, Id: R01 GM039565
  • Agency: NIGMS NIH HHS, Id: R37 GM039565

Publication data is provided by the National Library of Medicine ® and PubMed ®. Data is retrieved from PubMed ® on a weekly schedule. For terms and conditions see the National Library of Medicine Terms and Conditions.

We have not found any resources mentioned in this publication.