Biology:Keratin 7
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Keratin, type II cytoskeletal 7 also known as cytokeratin-7 (CK-7) or keratin-7 (K7) or sarcolectin (SCL) is a protein that in humans is encoded by the KRT7 gene.[1][2][3] Keratin 7 is a type II keratin. It is specifically expressed in the simple epithelia lining the cavities of the internal organs and in the gland ducts and blood vessels.
Function
Keratin-7 is a member of the keratin gene family. The type II cytokeratins consist of basic or neutral proteins which are arranged in pairs of heterotypic keratin chains coexpressed during differentiation of simple and stratified epithelial tissues. This type II cytokeratin is specifically expressed in the simple epithelia lining the cavities of the internal organs and in the gland ducts and blood vessels. The genes encoding the type II cytokeratins are clustered in a region of chromosome 12q12-q13. Alternative splicing may result in several transcript variants; however, not all variants have been fully described.[3]
Keratin-7 is found in simple glandular epithelia, and in transitional epithelium. Epithelial cells of the lung and breast both contain keratin-7, but some other glandular epithelia, such as those of the colon and prostate, do not.
Immunohistochemistry
Because the keratin-7 antigen is found in both healthy and neoplastic cells, antibodies to CK7 can be used in immunohistochemistry to distinguish ovarian and transitional cell carcinomas (staining positive) from colonic and prostate cancers (negative), respectively. It is commonly used together with CK20 when making such diagnoses.[4]
References
- ↑ "Three epidermal and one simple epithelial type II keratin genes map to human chromosome 12". Cytogenetics and Cell Genetics 57 (1): 33–8. Aug 1991. doi:10.1159/000133109. PMID 1713141.
- ↑ "New consensus nomenclature for mammalian keratins". The Journal of Cell Biology 174 (2): 169–74. Jul 2006. doi:10.1083/jcb.200603161. PMID 16831889.
- ↑ 3.0 3.1 "Entrez Gene: KRT7 keratin 7". https://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=3855.
- ↑ Leong, Anthony S-Y; Cooper, Kumarason; Leong, F Joel W-M (2003). Manual of Diagnostic Cytology (2 ed.). Greenwich Medical Media, Ltd.. p. 173. ISBN 978-1-84110-100-2.
Further reading
- "Cytokeratins and cell differentiation in the pancreas". The Journal of Pathology 184 (3): 234–9. Mar 1998. doi:10.1002/(SICI)1096-9896(199803)184:3<234::AID-PATH28>3.0.CO;2-D. PMID 9614373.
- "Sequence and expression of a human type II mesothelial keratin". The Journal of Cell Biology 101 (6): 2366–73. Dec 1985. doi:10.1083/jcb.101.6.2366. PMID 2415537.
- "Tissue distribution of keratin 7 as monitored by a monoclonal antibody". Experimental Cell Research 170 (1): 235–49. May 1987. doi:10.1016/0014-4827(87)90133-9. PMID 2436934.
- "Isolation, sequence, and differential expression of a human K7 gene in simple epithelial cells". The Journal of Cell Biology 107 (4): 1337–50. Oct 1988. doi:10.1083/jcb.107.4.1337. PMID 2459129.
- "Oligo-capping: a simple method to replace the cap structure of eukaryotic mRNAs with oligoribonucleotides". Gene 138 (1–2): 171–4. Jan 1994. doi:10.1016/0378-1119(94)90802-8. PMID 8125298.
- "A pancreatic cancer-specific expression profile". Oncogene 13 (8): 1819–30. Oct 1996. PMID 8895530.
- "Construction and characterization of a full length-enriched and a 5'-end-enriched cDNA library". Gene 200 (1–2): 149–56. Oct 1997. doi:10.1016/S0378-1119(97)00411-3. PMID 9373149.
- "[Mucinous adenocarcinoma of the urachus synchronic with colorectal adenocarcinoma. Value of immunohistochemistry in the differential diagnosis]". Actas Urologicas Españolas 22 (6): 515–8. Jun 1998. PMID 9734130.
- "Sarcolectin (SCL): structure and expression of the recombinant molecule". Biochimie 81 (7): 709–15. Jul 1999. doi:10.1016/S0300-9084(99)80128-X. PMID 10492017.
- "Molecular interaction between human tumor marker protein p150, the largest subunit of eIF3, and intermediate filament protein K7". Journal of Cellular Biochemistry 80 (4): 483–90. 2001. doi:10.1002/1097-4644(20010315)80:4<483::AID-JCB1002>3.0.CO;2-B. PMID 11169732.
- "Protein-protein interaction panel using mouse full-length cDNAs". Genome Research 11 (10): 1758–65. Oct 2001. doi:10.1101/gr.180101. PMID 11591653.
- "Cluster analysis of an extensive human breast cancer cell line protein expression map database". Proteomics 2 (2): 212–23. Feb 2002. doi:10.1002/1615-9861(200202)2:2<212::AID-PROT212>3.0.CO;2-H. PMID 11840567.
- "Nucleophosmin-anaplastic lymphoma kinase (NPM-ALK), a novel Hsp90-client tyrosine kinase: down-regulation of NPM-ALK expression and tyrosine phosphorylation in ALK(+) CD30(+) lymphoma cells by the Hsp90 antagonist 17-allylamino,17-demethoxygeldanamycin". Cancer Research 62 (5): 1559–66. Mar 2002. PMID 11888936.
- "Changing pattern of cytokeratin 7 and 20 expression from normal epithelium to intestinal metaplasia of the gastric mucosa and gastroesophageal junction". Histology and Histopathology 17 (2): 445–54. Apr 2002. PMID 11962749.
- "Translational regulation of human papillomavirus type 16 E7 mRNA by the peptide SEQIKA, shared by rabbit alpha(1)-globin and human cytokeratin 7". Journal of Virology 76 (14): 7040–8. Jul 2002. doi:10.1128/JVI.76.14.7040-7048.2002. PMID 12072504.
- "Cloning of human, murine, and marsupial keratin 7 and a survey of K7 expression in the mouse". Biochemical and Biophysical Research Communications 297 (4): 818–27. Oct 2002. doi:10.1016/S0006-291X(02)02288-X. PMID 12359226.
- "A proteomics strategy to elucidate functional protein-protein interactions applied to EGF signaling". Nature Biotechnology 21 (3): 315–8. Mar 2003. doi:10.1038/nbt790. PMID 12577067.
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