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Updated: Jul 18, 2026
10:52
Reconstitution of Basic Mitotic Spindles in Spherical Emulsion Droplets
Published on: August 13, 2016
Stu2 promotes mitotic spindle elongation in anaphase
F Severin1, B Habermann, T Huffaker
1Max Planck Institute for Molecular Cell Biology and Genetics, Pfotenhauerstrasse, 01307 Dresden, Germany.
The Journal of Cell Biology
|April 20, 2001
Summary
Microtubule stabilization during anaphase B in yeast requires Stu2, while Kip3 opposes this. A balance between these microtubule-stabilizing and destabilizing factors ensures correct spindle elongation for chromosome segregation.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- Mitotic spindle elongation during anaphase B is crucial for accurate chromosome segregation.
- The regulation of spindle length involves complex molecular mechanisms.
- Budding yeast Saccharomyces cerevisiae serves as a model organism for studying cell division.
Purpose of the Study:
- To investigate the molecular mechanisms controlling spindle length during anaphase B in Saccharomyces cerevisiae.
- To identify key proteins involved in microtubule stabilization and destabilization during spindle elongation.
- To understand the interplay between microtubule-associated proteins and kinesins in regulating mitotic spindle dynamics.
Main Methods:
- Utilized budding yeast Saccharomyces cerevisiae as the model system.
- Investigated the role of the microtubule-associated protein Stu2 in microtubule stabilization.
- Examined the function of the kinesin-related protein Kip3 in opposing microtubule stabilization.
- Performed phylogenetic analysis of kinesin proteins.
Main Results:
- Demonstrated that microtubule stabilization during anaphase B is dependent on the microtubule-associated protein Stu2.
- Showed that the activity of Stu2 is antagonized by the kinesin-related protein Kip3.
- Identified Kip3 as the Saccharomyces cerevisiae orthologue of the microtubule-destabilizing kinesin I subfamily.
- Provided evidence for a balance between microtubule-stabilizing and destabilizing factors in regulating spindle length.
Conclusions:
- A balance between microtubule-stabilizing (Stu2) and microtubule-destabilizing (Kip3) factors is essential for proper spindle elongation during anaphase B.
- Evolutionarily conserved mechanisms regulate spindle length through the opposing activities of specific proteins.
- Understanding this balance is key to comprehending accurate chromosome segregation during cell division.
Related Concept Videos
02:27The Mitotic Spindle
The mitotic spindle—or spindle apparatus—is a eukaryotic, cytoskeletal structure made up of long protein fibers called microtubules. Formed during cell division, the spindle separates sister chromatids and moves them to opposite ends of a parental cell, where the now individual chromosomes are distributed to two daughter cell nuclei.
The bipolar configuration of the mitotic spindle facilitates chromosomal segregation, preparing the cell for division. One mechanism that ensures bipolar mitotic...
The bipolar configuration of the mitotic spindle facilitates chromosomal segregation, preparing the cell for division. One mechanism that ensures bipolar mitotic...
02:50Spindle Assembly
Spindle assembly occurs through three, often coexisting, pathways – the centrosome-mediated pathway, the chromatin-mediated pathway, and the microtubule-mediated pathway – collectively contributing to form a robust spindle apparatus.
In most cells, centrosomes are the primary microtubule nucleation centers. In the centrosome-mediated pathway, the G2-prophase transition triggers centrosome maturation and increased microtubule nucleation. Progressive nucleation results in a microtubule array...
In most cells, centrosomes are the primary microtubule nucleation centers. In the centrosome-mediated pathway, the G2-prophase transition triggers centrosome maturation and increased microtubule nucleation. Progressive nucleation results in a microtubule array...
02:19The Spindle Assembly Checkpoint
The spindle assembly checkpoint is a molecular surveillance mechanism ensuring the fidelity of chromosome segregation during anaphase. The checkpoint monitors the completion of all the prerequisite steps before chromosome segregation to determine whether the segregation process should proceed or be delayed.
Many proteins function together to control the spindle assembly checkpoint. Mutations affecting these proteins may allow cells to proceed into anaphase prematurely, resulting in the...
Many proteins function together to control the spindle assembly checkpoint. Mutations affecting these proteins may allow cells to proceed into anaphase prematurely, resulting in the...
01:39Anaphase A and B
Microtubules form through the end-to-end polymerization of tubulin heterodimers. Kinetochore microtubules originate from the spindle poles, and their plus-ends connect with the kinetochores on sister-chromatids. Ndc80 protein complexes, present on the kinetochore, form low-affinity links with the plus end of these kinetochore microtubules.
Plus-end depolymerization releases tubulin heterodimers from the terminal region of the microtubule. As tubulin subunits are lost, the Ndc80 complexes detach...
Plus-end depolymerization releases tubulin heterodimers from the terminal region of the microtubule. As tubulin subunits are lost, the Ndc80 complexes detach...
02:19The Spindle Assembly Checkpoint
The spindle assembly checkpoint is a molecular surveillance mechanism ensuring the fidelity of chromosome segregation during anaphase. The checkpoint monitors the completion of all the prerequisite steps before chromosome segregation to determine whether the segregation process should proceed or be delayed.
Many proteins function together to control the spindle assembly checkpoint. Mutations affecting these proteins may allow cells to proceed into anaphase prematurely, resulting in the...
Many proteins function together to control the spindle assembly checkpoint. Mutations affecting these proteins may allow cells to proceed into anaphase prematurely, resulting in the...
01:39Anaphase A and B
Microtubules form through the end-to-end polymerization of tubulin heterodimers. Kinetochore microtubules originate from the spindle poles, and their plus-ends connect with the kinetochores on sister-chromatids. Ndc80 protein complexes, present on the kinetochore, form low-affinity links with the plus end of these kinetochore microtubules.
Plus-end depolymerization releases tubulin heterodimers from the terminal region of the microtubule. As tubulin subunits are lost, the Ndc80 complexes detach...
Plus-end depolymerization releases tubulin heterodimers from the terminal region of the microtubule. As tubulin subunits are lost, the Ndc80 complexes detach...