" These structures can have persistence lengths of 3-4 mm, which is several orders of magnitude higher than the average cellular diameter.
CLASP proteins bind one end of these structures and help inhibit a process called "catastrophe." These structures can have persistence lengths of 3-4 mm, which is several orders of magnitude higher than the average cellular diameter. These structures can be severed by katanin. Drugs such as paclitaxel stabilize these structures and prevent their depolymerization, where colchicine prevents its dimeric subunits from coming together. Shortening of these structure at the kinetochore ends of the spindle apparatus helps chromosomes walk towards poles during mitosis and meiosis. For 10 points, identify these structures which are components of the cytoskeleton and which are made of tubulin proteins. 
CLASP proteins bind one end of these structures and help inhibit a process called "catastrophe.
{microtubules}