Cytoskeleton

Cytoskeleton is a complex, dynamic network of interlinking protein filaments present in the cytoplasm of all cells, including bacteria and archaea. The cytoskeletal systems of different organisms are composed of similar proteins. In eukaryotes, the cytoskeletal matrix is a dynamic structure composed of three main proteins, which are microfilaments, intermediate filaments and microtubules.

Structure and Function

The cytoskeleton provides the cell with structure and shape, and by excluding macromolecules from some of the cytosol, it adds to the level of macromolecular crowding in this compartment. Cytoskeletons are also involved in intracellular transport and cellular division. For example, the mitotic spindle (which is required for mitosis) is composed of cytoskeleton filaments.

Components

Microfilaments

Microfilaments, also called actin filaments, are composed of linear polymers of G-actin proteins, and generate force by length changes to the filament as a whole.

Intermediate Filaments

Intermediate filaments are a part of the cytoskeleton that provide cellular support and resist shear stress.

Microtubules

Microtubules are the largest element of the cytoskeleton and are made up of 13 protofilaments that are composed of tubulin.

Role in Cell Division

During cell division, the cytoskeleton system undergoes a dramatic reorganization and is responsible for the formation of the mitotic spindle and cytokinesis.

See Also

• Cell biology
• Cell membrane
• Cell nucleus

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