The cytoskeleton is a dynamic three-dimensional structure that functions in cell mobility, intracellular movement, mitosis, cytokinesis, and maintenance of cell shape. The cytoskeleton is composed of three types of filaments including 1) microfilaments, 2) microtubules, and 3) intermediate filaments. Microfilaments are composed of Actin monomers whereas microtubules are composed of Tubulin monomers. The composition of intermediate filaments varies from one cell type to another as well as within a single cell. While the role of intermediate filaments is primarily structural, both microtubules and microfilaments are involved in active processes which require rapid assembly and disassembly of their monomeric units.