Type I keratins (or Type I cytokeratins) are

cytokeratin Cytokeratins are keratin proteins found in the intracytoplasmic cytoskeleton of epithelial tissue. They are an important component of intermediate filaments, which help cells resist mechanical stress. Expression of these cytokeratins within epit ...

s that constitute the Type I

intermediate filaments Intermediate filaments (IFs) are cytoskeletal structural components found in the cells of vertebrates, and many invertebrates. Homologues of the IF protein have been noted in an invertebrate, the cephalochordate '' Branchiostoma''. Intermedi ...

(IFs) of the intracytoplasmatic cytoskeleton, which is present in all mammalian epithelial cells. Most of the type I keratins consist of acidic, low molecular weight

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, respo ...

s which in vivo are arranged in pairs of heterotypic Type I and Type II keratin chains, coexpressed during differentiation of simple and stratified epithelial tissues. Type I keratins are encoded on

chromosome 17 Chromosome 17 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 17 spans more than 83 million base pairs (the building material of DNA) and represents between 2.5 and 3% of the total D ...

q and encompasses: K9, K10, K11, K12, K13, K14, K15, K16, K17, K18, K19 and K20. Their molecular weight ranges from 40 kDa (K19) to 64 kDa (K9).

External links

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Proteopedia page on keratins
Keratins {{Fibrous proteins

See also

External links