Keratins and the skin

Keratins are the epithelial-specific members of the superfamily of intermediate filament (IF) genes and proteins. The 28 type I and 26 type II keratin genes are regulated in a pairwise fashion, reflecting the heteromeric nature of the 10. nm filaments they form, as well as in a tissue-specific and differentiation-dependent fashion in the body, giving rise to expression patterns that are very useful to define the status of epithelia in health and disease. Keratin IFs fulfill two major functions: structural support, without which incident physical trauma exposes an inherent fragility and leads to loss of cell integrity, and regulation of several basic cellular processes such as growth, proliferation, apoptosis, made possible by interactions with various cellular proteins.