Cytoskeleton is a form of rigid structure or scaffolding contained within the cytoplasm, and necessary for cellular structure, motion and cell division. It is classified as an organelle. All cells contain a cytoskeleton of some sort.
The cytoskeleton is a dynamic structure that helps maintain cell shape, organizes internal cellular organelles, enables cellular motion using structures such as flagella and cilia, and enables certain types of intracellular transport.
In the eukaryotic cell, the cytoskeleton is made up primarily of actin filaments, which are about 7 nanometers (nm) in diameter; of intermediate filaments, about 8-11 nm in diameter; and microtubules, which are more complex structures. Actin filaments form pseudopodia and microvilli and can participate in transduction and cytokinesis. They are necessary for muscle contraction. Intermediate filaments come in several different types and provide several different functions, primarily structure related. Microtubules play important roles in intracellular transport, transporting organelles and vesicles, and creating cilia and flagella.
Prokaryotes also have a cytoskeleton, though its genetic sequence is quite different from that of the eukaryote. Still, recent evidence shows that most of the protein parts cytoskeleton in eukaryotic cells have homologues in the prokaryotic cell.
Web Resources On Cytoskeleton
The Cytoskeleton of Cells
Book Resources On Cytoskeleton
Mechanics of Motor Proteins and the Cytoskeleton by Jonathon Howard
Molecules of the Cytoskeleton by Amos & Amos