List of keratins expressed in the human integumentary system

Keratins in the Human Integumentary System

The human integumentary system is a complex structure that serves as the body's primary barrier against the external environment. It is composed of various types of cells and tissues, with keratins playing a pivotal role in its function and integrity. Keratins are a diverse family of fibrous proteins that are crucial for the structural and protective qualities of epithelial cells. In the human integumentary system, which includes the skin, hair, and nails, different types of keratins are expressed, each contributing to the unique properties of these tissues.

Types of Keratins in the Human Integumentary System

Keratins can be broadly classified into two types: type I (acidic) and type II (basic to neutral). These proteins form heterodimers, which then assemble into intermediate filaments, providing structural support to epithelial cells. The specific types of keratins expressed in the integumentary system are adapted to the mechanical and environmental stresses experienced by the skin, hair, and nails.

Skin Keratins

The epidermis, the outermost layer of the skin, predominantly expresses keratins that contribute to its protective function. Key keratins include:

• Keratin 5 (KRT5) and Keratin 14 (KRT14) - These form a pair that is crucial in the basal layer of the epidermis.
• Keratin 1 (KRT1) and Keratin 10 (KRT10) - Expressed in the spinous and granular layers, these keratins are essential for the formation of the skin barrier.

Hair Keratins

Hair is primarily composed of keratins that provide it with strength and flexibility. Important hair keratins include:

• Keratin 31 (KRT31) and Keratin 85 (KRT85) - These are expressed in the hair cortex and contribute to the hair's structural integrity.
• Keratin 71 (KRT71) - This keratin is involved in the formation of the hair cuticle, the outermost layer of the hair shaft.

Nail Keratins

Nails require hard keratins for their rigidity and durability. Key nail keratins are:

• Keratin 17 (KRT17) - Found in the nail bed, it plays a role in nail growth and health.
• Keratin 5 (KRT5) - Although also found in the skin, KRT5 is involved in the attachment of the nail plate to the nail bed.

Function of Keratins

Keratins provide mechanical support and protect epithelial cells from stress, damage, and apoptosis. They are involved in cellular processes such as signaling, growth, and differentiation. In the integumentary system, keratins contribute to the barrier function of the skin, the resilience of hair against physical and chemical damage, and the strength of nails.

Genetic and Clinical Significance

Mutations in keratin genes can lead to a variety of skin, hair, and nail disorders. For example, mutations in KRT5 and KRT14 are associated with Epidermolysis Bullosa Simplex, a condition characterized by fragile skin that blisters easily. Understanding the specific keratins expressed in the integumentary system is crucial for diagnosing and treating these conditions.

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See Also

• Epithelial Cells
• Protein Structure
• Genetic Disorders of the Integumentary System