List of keratins

Keratins are a diverse group of structural proteins that form the key structural material in the outer layer of human skin, as well as in hair, nails, and the epithelial cells of internal organs and glands. Keratins are a major component of cells in the epidermis, the outermost layer of the skin, providing it with its durability and protective capabilities. They are also essential for the structure and function of hair follicles, nails, and the epithelial cells of the digestive system, respiratory system, and urinary system. This article provides a list of keratins, highlighting their importance in various biological structures and functions.

Types of Keratins

Keratins can be broadly classified into two types: alpha-keratins and beta-keratins. Alpha-keratins are found in mammals, while beta-keratins are present in birds and reptiles. This classification is based on their secondary structure and the amino acid sequence.

Alpha-Keratins

Alpha-keratins are primarily found in mammals and are a key component of human skin, hair, and nails. They are characterized by their helical structure, forming coiled-coil dimers that assemble into filaments.

• Type I Keratins - These are acidic keratins and include:
  • Keratin 9 (KRT9), found in the epidermis of palms and soles
  • Keratin 10 (KRT10), expressed in the upper layers of the epidermis
  • Keratin 14 (KRT14), found in the basal layer of the epidermis
  • Keratin 16 (KRT16), involved in wound healing
  • Keratin 18 (KRT18), present in simple epithelial tissues
  • Keratin 19 (KRT19), the smallest keratin, found in many epithelial cells

• Type II Keratins - These are basic or neutral keratins and include:
  • Keratin 1 (KRT1), found in the epidermis of the skin, particularly in areas of high mechanical stress
  • Keratin 2 (KRT2), expressed in the upper spinous and granular layers of the epidermis
  • Keratin 5 (KRT5), found in the basal layer of the epidermis
  • Keratin 6 (KRT6), involved in wound healing
  • Keratin 17 (KRT17), expressed in the hair follicles and nails

Beta-Keratins

Beta-keratins are found in birds and reptiles and are responsible for the strength and rigidity of their scales, feathers, and claws. Unlike alpha-keratins, beta-keratins have a beta-sheet structure.

Function of Keratins

Keratins play a crucial role in providing mechanical strength and protection to epithelial cells against physical and chemical stresses. They are involved in various cellular functions, including cell growth, cell death, and protein synthesis. Keratins also contribute to the waterproofing of the skin, preventing excessive loss of water and protecting against dehydration.

Clinical Significance

Mutations in keratin genes can lead to a variety of skin disorders, hair disorders, and nail disorders. For example, mutations in the KRT5 and KRT14 genes can cause Epidermolysis Bullosa Simplex, a condition characterized by fragile skin that blisters easily. Similarly, mutations in KRT1 and KRT10 can lead to Ichthyosis, a disorder causing dry, thickened skin.

List of Keratins

This list is incomplete; you can help WikiMD by expanding it.

• Keratin 1 (KRT1)
• Keratin 2 (KRT2)
• Keratin 5 (KRT5)
• Keratin 6 (KRT6)
• Keratin 9 (KRT9)
• Keratin 10 (KRT10)
• Keratin 14 (KRT14)
• Keratin 16 (KRT16)
• Keratin 17 (KRT17)
• Keratin 18 (KRT18)
• Keratin 19 (KRT19)
• ...and more