Keratin Protein & the Epidermis

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  • 0:01 What Is the Epidermis?
  • 0:53 What Is Keratin?
  • 1:17 Keratin in Skin
  • 2:57 Keratin Diseases
  • 3:23 Lesson Summary
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Lesson Transcript
Instructor: Amanda Robb

Amanda holds a Masters in Science from Tufts Medical School in Cellular and Molecular Physiology. She has taught high school Biology and Physics for 8 years.

This lesson is about keratin and its role in the epidermis, or the skin. We will talk about what the skin is made of, what keratin protein looks like, how it works inside the skin, and what happens when keratin creates disease in the skin.

What is the Epidermis?

Ever wonder what's underneath your skin? What would happen if your skin couldn't hold itself together? That's what we're going to cover here (pun intended)! You'll learn all about the protein, keratin, and how it holds our skin together. Our skin is actually made of three layers; the epidermis, dermis, and hypodermis. They form a skin sandwich with the epidermis and hypodermis being the bread, and the dermis being the middle.

The epidermis is the layer we're interested in for this lesson. The epidermis is the outer layer of cells in the skin. It is made of flat, scale-like, cells called epithelial cells and specialized cells known as keratinocytes. These cells protect our body and prevent pathogens from penetrating the skin. An important protein called keratin, anchors the cells together and to the layer beneath it, the dermis.

What is Keratin?

Keratin is a protein inside cells. It exists in many types of cells but it is very important for epithelial cells, which make up the skin. Keratin is a type of filament protein, called an intermediate filament. These proteins form long strands inside the cell, hence the name filament. The filaments anchor the cells to each other, which prevents the cells from pulling apart.

Keratin in Skin

Keratin has two main functions in the skin:

1. To hold skin cells together to form a barrier

2. To form the outermost layer of our skin, that protects us from the environment.

To form a barrier, epithelial cells anchor together through proteins called desmosomes. Two epithelial cells line up next to each other and attach using desmosomes. The desmosomes are like glue holding the two cells together. Inside the cell are the keratin fibers, holding the desmosomes to the cell. Without the keratin fibers, the desmosomes would just pull the membrane of the cell away from the center. The keratin anchors the desmosomes to the cell and the desmosomes anchor the cells to each other. See the desmosome junction? The cells attach to each other, and the long filaments within the junction are keratin proteins.

Desmosome junctions in epithelial cells

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