Microtubules

Microtubules are a component of the cytoskeleton, found throughout the cytoplasm of all eukaryotic cells. They are involved in maintaining the structure of the cell and, together with microfilaments and intermediate filaments, they form the cytoskeleton.

Structure

Microtubules are hollow cylinders about 25 nanometers in diameter and 200 nanometers to 25 micrometers in length. They are composed of tubulin, a globular protein. Each tubulin molecule is made up of two subunits, alpha-tubulin and beta-tubulin.

Function

Microtubules have several functions. They provide platforms for intracellular transport and are involved in a variety of cellular processes, including the movement of secretory vesicles, organelles, and intracellular macromolecular assemblies. They can grow or shrink in order to generate force, and they are also involved in cell division, serving as the structural element that separates the chromosomes.

Role in Cell Division

During cell division, the microtubule network forms the mitotic spindle, which is used to separate the chromosomes into the two daughter cells. The spindle is formed from two centrosomes, which are structures in the cell that serve as organizing centers for the microtubules.

Diseases and Disorders

Defects in microtubules and their associated proteins are associated with a range of diseases and disorders, including neurodegenerative diseases, cancer, and birth defects. For example, mutations in the tubulin genes can lead to malformations of cortical development, which can cause epilepsy, intellectual disability, and autism.

See Also

• Cytoskeleton
• Cell division
• Mitotic spindle
• Tubulin

References

Microtubules Resources
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