ID:K1C20_HUMAN DESCRIPTION: RecName: Full=Keratin, type I cytoskeletal 20; AltName: Full=Cytokeratin-20; Short=CK-20; AltName: Full=Keratin-20; Short=K20; AltName: Full=Protein IT; FUNCTION: Plays a significant role in maintaining keratin filament organization in intestinal epithelia. When phosphorylated, plays a role in the secretion of mucin in the small intestine (By similarity). SUBUNIT: Heterotetramer of two type I and two type II keratins. Associates with KRT8. SUBCELLULAR LOCATION: Cytoplasm. TISSUE SPECIFICITY: Expressed predominantly in the intestinal epithelium. Expressed in luminal cells of colonic mucosa. Also expressed in the Merkel cells of keratinized oral mucosa; specifically at the tips of some rete ridges of the gingival mucosa, in the basal layer of the palatal mucosa and in the taste buds of lingual mucosa. DEVELOPMENTAL STAGE: First detected at embryonic week 8 in individual 'converted' simple epithelial cells of the developing intestinal mucosa. In later fetal stages, synthesis extends over most goblet cells and a variable number of villus enterocytes. In the developing gastric and intestinal mucosa, expressed in all enterocytes and goblet cells as well as certain 'low- differentiated' columnar cells, whereas the neuroendocrine and Paneth cells are negative. PTM: Hyperphosphorylation at Ser-13 occurs during the early stages of apoptosis but becomes less prominent during the later stages. Phosphorylation at Ser-13 also increases in response to stress brought on by cell injury (By similarity). PTM: Proteolytically cleaved by caspases during apoptosis. Cleavage occurs at Asp-228. MISCELLANEOUS: There are two types of cytoskeletal and microfibrillar keratin: I (acidic; 40-55 kDa) and II (neutral to basic; 56-70 kDa). SIMILARITY: Belongs to the intermediate filament family.
The RNAfold program from the Vienna RNA Package is used to perform the secondary structure predictions and folding calculations. The estimated folding energy is in kcal/mol. The more negative the energy, the more secondary structure the RNA is likely to have.
Pfam Domains: PF00038 - Intermediate filament protein
SCOP Domains: 46579 - Prefoldin 64593 - Intermediate filament protein, coiled coil region 90257 - Myosin rod fragments
ModBase Predicted Comparative 3D Structure on P35900
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Orthologous Genes in Other Species
Orthologies between human, mouse, and rat are computed by taking the best BLASTP hit, and filtering out non-syntenic hits. For more distant species reciprocal-best BLASTP hits are used. Note that the absence of an ortholog in the table below may reflect incomplete annotations in the other species rather than a true absence of the orthologous gene.
US Server
Sequence and Links to Tools and Databases 
Common Gene Haplotype Alleles 
