ABSTRACT
This chapter describes several main types of filaments, the basic principles underlying their assembly and disassembly, and their individual peculiarities. It also describes how other proteins interact with the three main filament systems, enabling the cell to establish and maintain internal order, to shape and remodel its surface, to move organelles in a directed manner from one place to another, and when appropriate to move itself to new locations. The cytoskeleton pulls the chromosomes apart at mitosis and then splits the dividing cell into two. The cytoskeleton's varied functions depend on the behavior of three families of protein molecules, which assemble to form three main types of filaments. The chapter discusses the properties of the proteins that make up the filaments of the cytoskeleton. The polarization of the actin cytoskeleton is assisted by the microtubule cytoskeleton, consisting of long microtubules that emanate from a single microtubule organizing center located in front of the nucleus.
