Abstract: Keratin 14 is a class I keratin and is found associated with keratin 5 in mitotically active keratinocytes of all stratified squamous epithelia. The function of the keratin filaments in the epidermis is to impart mechanical integrity to the cells, without which the cells become fragile and prone to rupturing. This chapter presents a study in which homozygotes were born normally and appeared normal until two days after birth, when they became frail and began to show signs of gross blistering over their body surfaces, especially the paws, legs, and ears. Light microscopy revealed blister formation in the basal layer of the mutant epidermis, with the suprabasal layers remaining intact. Ultrastructural analysis of skin showed paucity of keratin filament bundles in the basal layer. There was a residual minor network of keratin filaments attached to hemidesmosomes and desmosomes in mutant cells. These filaments were sparse and wispy rather than in bundles. The suprabasal layers were indistinguishable from normal skin. Protein analysis of two-day-old mutant animals showed no expression of keratin 14 in the skin but the presence of keratin 5 at a high level. However, no other keratin proteins are upregulated to compensate for the loss of keratin 14. Protein analysis showed that the levels of keratin 15 remained the same in normal and mutant tissues. These results confirm that the function of the epidermal keratin filaments is to impart mechanical integrity to cells.
Publication Year: 1998
Publication Date: 1998-01-01
Language: en
Type: book-chapter
Indexed In: ['crossref']
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