What kinds of proteins make up the mitotic spindle?
1 Answer
May 28, 2017
Mitotic spindle is mainly made of microtubules. These microtubules are made by polymerisation of globular tubulin proteins.
There are three types of microtubules in a spindle apparatus.
- In interpolar microtubules, polymerisation of tubulin takes place near equatorial region of spindle apparatus while tubulin subunits are lost near polar regions.
- Chromosomes of a dividing cell get attached to kinetochore microtubules.
- In the polar region of apparatus, there are astral microtubules.
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There are other important proteins present in the dynamic spindle apparatus: and one such protein is kinesin while the other is dynein.
Both kinesin and dynein are included in a category called motor protein. Both proteins move along microtubules but in opposite directions.
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Kinesin molecules help in elongation of interpolar microtubules during anaphase, while dynein molecules help in poleward migration of sister chromatids (hence in chromatid separation during anaphase).
