Cytokeratin



Cytokeratins are proteins that form intermediate filaments. Cytokeratin filaments are then part of the cytoskeleton of the cells forming the epithelium. We know more than 25 "soft cytokeratins". The epithelium that forms the hard skin adnexa (hair, nails) also contains "hard cytokeratins", of which there are about 15 different types.