Keratin 5 Keratin 5 Keratin 5, also known as KRT5, K5, or CK5, is a protein that is encoded in humans by the "KRT5" gene. It dimerizes with keratin 14 and forms the intermediate filaments (IF) that make up the cytoskeleton of basal epithelial cells. This protein is involved in several diseases including epidermolysis bullosa simplex and breast and lung cancers. Keratin 5, like other members of the keratin family, is an intermediate filament protein. These polypeptides are characterized by a 310 residue central rod domain that consists of four alpha helix segments (helix 1A, 1B, 2A, and 2B) connected by three
Keratin about 10 µm across, with cores and coating, and may be arranged in up to 10 layers, also in plaques of variable shape. Adult hornets also use silk as a glue, as do spiders. Some infectious fungi, such as those that cause athlete's foot and ringworm (i.e. the dermatophytes), or "Batrachochytrium dendrobatidis" (Chytrid fungus), feed on keratin. Diseases caused by mutations in the keratin genes include: Keratin expression is helpful in determining epithelial origin in anaplastic cancers. Tumors that express keratin include carcinomas, thymomas, sarcomas and trophoblastic neoplasms. Furthermore, the precise expression pattern of keratin subtypes allows prediction of the