The cytoskeleton is a complex network of protein filaments that provides structure, support, and organization to cells. It is composed of three main types of protein filaments:

* Microtubules: These are hollow tubes made of tubulin protein. They provide structural support, facilitate cell movement, and transport organelles within the cell.

* Microfilaments: These are thin, solid fibers made of actin protein. They are involved in cell shape, muscle contraction, and cell division.

* Intermediate filaments: These are rope-like fibers made of various proteins, depending on the cell type. They provide structural support and help to anchor organelles.

Together, these protein fibers form a dynamic and constantly changing network that allows cells to maintain their shape, move, and interact with their environment.