Keratin, type I cytoskeletal 4 also known as cytokeratin-4 (CK-4) or keratin-4 (K4) is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

that in humans is encoded by the ''KRT4''

gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...

. Keratin 4 is a

type II cytokeratin Type II keratins (or Type II cytokeratins) constitutes the Type II intermediate filaments (IFs) of the intracytoplasmatic cytoskeleton, which is present in all mammalian epithelial cells. The type 2 cytokeratins consist of basic or neutral, high mol ...

. It is specifically found in differentiated layers of the mucosal and esophageal epithelia together with

keratin 13 Keratin 13 (or cytokeratin 13) is a protein that in humans is encoded by the ''KRT13'' gene. Keratin 13 is a type I cytokeratin, it is paired with keratin 4 and found in the suprabasal layers of non-cornified stratified epithelia. Mutations in ...

. Mutations in the genes encoding this protein have been associated with

White Sponge Nevus White sponge nevus (WSN) is an autosomal dominant condition of the oral mucosa (the mucous membrane lining of the mouth). It is caused by a mutations in certain genes coding for keratin, which causes a defect in the normal process of keratinizati ...

, characterized by

oral The word oral may refer to: Relating to the mouth * Relating to the mouth, the first portion of the alimentary canal that primarily receives food and liquid **Oral administration of medicines ** Oral examination (also known as an oral exam or or ...

, esophageal, and

anal Anal may refer to: Related to the anus *Related to the anus of animals: ** Anal fin, in fish anatomy ** Anal vein, in insect anatomy ** Anal scale, in reptile anatomy *Related to the human anus: ** Anal sex, a type of sexual activity involving s ...

leukoplakia Oral leukoplakia is a ''potentially malignant disorder'' affecting the oral mucosa. It is defined as "essentially an oral mucosal white lesion that cannot be considered as any other definable lesion." Oral leukoplakia is a white patch or plaque th ...

References

Further reading