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.



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.



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).