Problem
During prophase, the array of cytosolic microtubules that exists during interphase must be replaced with the mitotic spindle.
1) The enyzme katanin (named after the Japanese katana) extracts tubulin subunits from the "middle" of microtubules promoting breakage. What do you think happens to the microtubule fragments after they break and why?
2) Also during formation of the spindle and bioorientation, some microtubules are not nucleated by MTOC and instead contain the protein Patronin (named after a spell from Harry Potter) at their minus ends. What do you think is the role of Patronin at microtubule minus ends during early mitosis and why?