Keratins

Keratins are a group of tough, fibrous proteins that form the structural framework of epithelial cells, which are cells that line the surfaces and cavities of the body. Keratins are produced by a wide variety of epithelial cells and are assembled into filaments.

Structure

Keratins are characterized by their high sulfur content, which is due to the presence of large amounts of the amino acid cysteine. This allows for the formation of disulfide bonds between keratin molecules, resulting in a very tough and resilient structure.

Function

Keratins play a key role in the mechanical support, protection, and repair of epithelial cells. They also contribute to the formation of various appendages of the skin, such as hair, nails, and feathers.

Types

There are two main types of keratins: alpha-keratins and beta-keratins. Alpha-keratins are found in mammals and are the main component of hair and nails. Beta-keratins are found in birds and reptiles and are the main component of feathers, beaks, and claws.

Clinical significance

Mutations in keratin genes can lead to a variety of genetic disorders, including epidermolysis bullosa simplex, Ehlers-Danlos syndrome, and pachyonychia congenita. In addition, abnormal expression or function of keratins can be a marker for various types of cancer.

See also

• Epithelium
• Hair
• Nail (anatomy)
• Feather

Keratins Resources
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