Figure 1.

The dynamic nature of cytoskeleton is due to cycles of microtubule catastrophes. (a) Model structure of assembled cytoskeleton. The variety of shapes and sizes of the microtubule cytoskeleton is as great as the number of different cell types. In interphase, microtubules are long and stable because there are almost no catastrophes. (b) In mitosis, catastrophes are relatively frequent, resulting in highly dynamic microtubules that reach a steady-state length after a few minutes of growth (c). (d) After the segregation of chromatids, a new cycle of depolymerization and polymerization begins, resulting in a new stable microtubule cytoskeleton in daughter's cells (d). Blue and red arrows indicate effects of stabilizing and destabilizing agents, all resulting in cell cycle arrest.