Question

2. When cells enter mitosis, their cytoplasmic microtubules must rapidly disappear to be replaced by microtubules that polymerize to form the mitotic spindle. Katanin, an enzyme named after the Japanese Samurai sword, is activated at the onset of mitosis. It chops the existing microtubules into short pieces. How does the creation of many short microtubule fragments by katanin lead to rapid microtubule disassembly in preparation for mitosis? Explain your reasoning.

Answer 1

Katanin enhances the depolymerization of existing microtubules as it chops off microtubules into short pieces. Also, Katanin reduces the polymer mass and destabilizes the internal network of microtubules and hence due to instability and their very small size, microtubules diminish in preparation for mitosis.