Contents

Search

keratin, type I cytoskeletal 20; cytokeratin-20; CK-20; keratin-20; K20; protein IT (KRT20)

Function: - role in maintaining keratin filament organization in intestinal epithelia - when phosphorylated, plays a role in the secretion of mucin in the small intestine - hyperphosphorylation at Ser-13 occurs during early stages of apoptosis but becomes less prominent during later stages - phosphorylation at Ser-13 also increases in response to stress brought on by cell injury (putative) - proteolytically cleaved by caspases during apoptosis; cleavage occurs at Asp-228 - associates with KRT8 Structure: - type 1 cytokeratin - heterotetramer of 2 type 1 & 2 type 2 cytokeratins - 46 kD low molecular weight keratin - belongs to the intermediate filament family Compartment: cytoplasm Expression: - 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 & in the taste buds of lingual mucosa - 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 & a variable number of villus enterocytes - in the developing gastric & intestinal mucosa, expressed in all enterocytes & goblet cells as well as certain 'low- differentiated' columnar cells, whereas the neuroendocrine & Paneth cells are negative Pathology: - stain positive with antibody - colorectal adenocarcinoma - pancreatic adenocarcinoma - mucinous ovarian carcinoma - Merkel cell carcinoma - transitional cell carcinoma - breast carcinoma (especially papillary & mucinous) - lung adenocarcinoma - stain negatively with antibody - hepatocellular carcinoma - renal carcinoma - prostate adenocarcinoma - squamous carcinomas & small cell carcinomas

Related

cytokeratin-20 Ag in tissue

General

cytokeratin, epithelial keratins or soft alpha-keratins phosphoprotein

Properties

CONFIGURATION: oligomer SIZE: entity length = 424 aa MW = 48 kD COMPARTMENT: cytoplasm MOTIF: Head {1-69} MOTIF: Ser phosphorylation site {S13} Ser phosphorylation site {S14} Ser phosphorylation site {S34} Rod {70-377} MOTIF: Coil 1A {70-105} Linker 1 {106-123} Coil 1B {124-215} Linker 12 {216-238} peptide motif {228-229} Coil 2 {239-377} Tail {378-424}

Database Correlations

OMIM 608218 UniProt P35900 Pfam PF00038 Entrez Gene 54474 Kegg hsa:54474

References

  1. Dabbs. Diagnostic Immunohistochemistry. Churchill Livingstone, 2002. page 167.
  2. Entrez Gene :accession 54474
  3. UniProt :accession P35900