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12:20
Preparation of Segmented Microtubules to Study Motions Driven by the Disassembling Microtubule Ends
Published on: March 15, 2014
The kinetochore-bound Ska1 complex tracks depolymerizing microtubules and binds to curved protofilaments
Jens C Schmidt1, Haribabu Arthanari, Andras Boeszoermenyi
1Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA.
Developmental Cell
|October 23, 2012
Summary
The Ska1 complex tracks depolymerizing microtubules, enabling kinetochore attachment. This tracking ability is imparted to the Ndc80 complex, defining a novel kinetochore-microtubule interface crucial for chromosome segregation.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Accurate chromosome segregation during mitosis relies on kinetochore attachment to depolymerizing microtubules.
- The mechanism by which kinetochores associate with dynamic microtubule ends, including curved protofilaments, remains unclear in vertebrates.
Purpose of the Study:
- To elucidate how kinetochores, specifically the Ska1 and Ndc80 complexes, interact with depolymerizing microtubules.
- To define the structural and functional basis of the kinetochore-microtubule interface during mitosis.
Main Methods:
- Investigated the interaction of Ska1 and Ndc80 complexes with microtubules using biochemical assays.
- Determined the structure of the Ska1 microtubule-binding domain and its regulation by Aurora B kinase.
- Assessed the tracking capabilities of Ska1 and Ndc80 complexes on depolymerizing microtubules.
Main Results:
- The Ska1 complex tracks depolymerizing microtubule ends, binding to both the lattice and curved protofilaments.
- The Ndc80 complex binds only to the straight microtubule lattice and lacks inherent tracking activity.
- Ska1 complex confers its microtubule tracking ability to the Ndc80 complex.
Conclusions:
- An integrated kinetochore-microtubule interface involving Ska1 and Ndc80 complexes associates with depolymerizing microtubules.
- Interaction with curved microtubule protofilaments by the Ska1 complex is key to tracking dynamic microtubule ends.
- This mechanism ensures stable kinetochore-microtubule attachment for proper chromosome segregation.
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