I believe keratin functions to prevent water loss from the skin. Keratin is a protein mostly found in the hair, skin and nails. It can also be found in internal organs and glands, it is a protective protein, less prone to scratching or tearing than other types of cells produced by the body. Therefore, keratin serves important structural and protective functions, especially in the epithelium, the have also been found to regulate cellular activities such as cell growth.
