Keratin 20, often abbreviated CK20, is a protein that in humans is encoded by the KRT20 gene. Keratin 20 is a type I cytokeratin. It is a major cellular protein of mature enterocytes and goblet cells and is specifically found in the gastric and intestinal mucosa. Alternative Names: Keratin K 20, Keratin 20 protein, Cytokeratin 20 protein, Keratin K-20 protein, Keratin K 20 protein, Keratin K-20, Keratin K20