Keratin 4 Explained

Keratin, type I cytoskeletal 4 also known as cytokeratin-4 (CK-4) or keratin-4 (K4) is a protein that in humans is encoded by the KRT4 gene.^{[1] [2]}

Keratin 4 is a type II cytokeratin. It is specifically found in differentiated layers of the mucosal and esophageal epithelia together with keratin 13. Mutations in the genes encoding this protein have been associated with White Sponge Nevus, characterized by oral, esophageal, and anal leukoplakia.^[3]

Further reading

• Leube RE, Bader BL, Bosch FX, etal . Molecular characterization and expression of the stratification-related cytokeratins 4 and 15 . J. Cell Biol. . 106 . 4 . 1249–61 . 1988 . 2452170 . 2114990 . 10.1083/jcb.106.4.1249 .
• Samen U, Eikmanns BJ, Reinscheid DJ, Borges F . The Surface Protein Srr-1 of Streptococcus agalactiae Binds Human Keratin 4 and Promotes Adherence to Epithelial HEp-2 Cells . Infect. Immun. . 75 . 11 . 5405–14 . 2007 . 17709412 . 2168289 . 10.1128/IAI.00717-07 .
• Barcelos AC, Sotto MN . Comparative analysis of the expression of cytokeratins (1, 10, 14, 16, 4), involucrin, filaggrin and e-cadherin in plane warts and epidermodysplasia verruciformis plane wart-type lesions . J. Cutan. Pathol. . 36 . 6 . 647–54 . 2009 . 19515043 . 10.1111/j.1600-0560.2008.01127.x . 205816580 .
• Terrinoni A, Candi E, Oddi S, etal . A glutamine insertion in the 1A alpha helical domain of the keratin 4 gene in a familial case of white sponge nevus . J. Invest. Dermatol. . 114 . 2 . 388–91 . 2000 . 10652003 . 10.1046/j.1523-1747.2000.00890.x . free .
• Zhang JM, Yang ZW, Chen RY, etal . Two new mutations in the keratin 4 gene causing oral white sponge nevus in Chinese family . Oral Dis . 15 . 1 . 100–5 . 2009 . 18992023 . 10.1111/j.1601-0825.2008.01498.x .
• Opitz OG, Jenkins TD, Rustgi AK . Transcriptional regulation of the differentiation-linked human K4 promoter is dependent upon esophageal-specific nuclear factors . J. Biol. Chem. . 273 . 37 . 23912–21 . 1998 . 9727005 . 10.1074/jbc.273.37.23912 . free .
• Gerhard DS, Wagner L, Feingold EA, etal . The Status, Quality, and Expansion of the NIH Full-Length cDNA Project: The Mammalian Gene Collection (MGC) . Genome Res. . 14 . 10B . 2121–7 . 2004 . 15489334 . 528928 . 10.1101/gr.2596504 .
• Wolfe BA, Takaki T, Petronczki M, Glotzer M . Polo-Like Kinase 1 Directs Assembly of the HsCyk-4 RhoGAP/Ect2 RhoGEF Complex to Initiate Cleavage Furrow Formation . PLOS Biol. . 7 . 5 . e1000110 . 2009 . 19468300 . 2680334 . 10.1371/journal.pbio.1000110 . Pellman . David . free .
• Ota T, Suzuki Y, Nishikawa T, etal . Complete sequencing and characterization of 21,243 full-length human cDNAs . Nat. Genet. . 36 . 1 . 40–5 . 2004 . 14702039 . 10.1038/ng1285 . free .
• Strausberg RL, Feingold EA, Grouse LH, etal . Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences . Proc. Natl. Acad. Sci. U.S.A. . 99 . 26 . 16899–903 . 2002 . 12477932 . 139241 . 10.1073/pnas.242603899 . 2002PNAS...9916899M . free .
• Presland RB, Dale BA . Epithelial structural proteins of the skin and oral cavity: function in health and disease . Crit. Rev. Oral Biol. Med. . 11 . 4 . 383–408 . 2000 . 11132762 . 10.1177/10454411000110040101 .
• Mischke D, Wild G . Polymorphic keratins in human epidermis . J. Invest. Dermatol. . 88 . 2 . 191–7 . 1987 . 2433356 . 10.1111/1523-1747.ep12525329 .
• Wanner R, Förster HH, Tilmans I, Mischke D . Allelic variations of human keratins K4 and K5 provide polymorphic markers within the type II keratin gene cluster on chromosome 12 . J. Invest. Dermatol. . 100 . 6 . 735–41 . 1993 . 7684424 . 10.1111/1523-1747.ep12475671 .
• Wanner R, Zhang J, Dorbic T, etal . The promoter of the HaCaT keratinocyte differentiation-related gene keratin 4 contains a functional AP-2 binding site . Arch. Dermatol. Res. . 289 . 12 . 705–8 . 1997 . 9452892 . 10.1007/s004030050265 . 7854003 .
• Sowa ME, Bennett EJ, Gygi SP, Harper JW . Defining the Human Deubiquitinating Enzyme Interaction Landscape . Cell . 138 . 2 . 389–403 . 2009 . 19615732 . 2716422 . 10.1016/j.cell.2009.04.042 .
• Burkard ME, Maciejowski J, Rodriguez-Bravo V, etal . Plk1 Self-Organization and Priming Phosphorylation of HsCYK-4 at the Spindle Midzone Regulate the Onset of Division in Human Cells . PLOS Biol. . 7 . 5 . e1000111 . 2009 . 19468302 . 2680336 . 10.1371/journal.pbio.1000111 . Pellman . David . free .
• Romano V, Bosco P, Rocchi M, etal . Chromosomal assignments of human type I and type II cytokeratin genes to different chromosomes . Cytogenet. Cell Genet. . 48 . 3 . 148–51 . 1988 . 2466616 . 10.1159/000132612 .

Notes and References

1. Barletta C, Batticane N, Ragusa RM, Leube R, Peschle C, Romano V . Subchromosomal localization of two human cytokeratin genes (KRT4 and KRT15) by in situ hybridization . Cytogenet. Cell Genet. . 54 . 3–4 . 148–50 . 1990 . 1702379 . 10.1159/000132979.
2. Schweizer J, Bowden PE, Coulombe PA, Langbein L, Lane EB, Magin TM, Maltais L, Omary MB, Parry DA, Rogers MA, Wright MW . New consensus nomenclature for mammalian keratins . J. Cell Biol. . 174 . 2 . 169–74 . July 2006 . 16831889 . 2064177 . 10.1083/jcb.200603161 .
3. Chao SC, Tsai YM, Yang MH, Lee JY . A novel mutation in the keratin 4 gene causing white sponge naevus . Br. J. Dermatol. . 148 . 6 . 1125–8 . June 2003 . 12828738 . 10.1046/j.1365-2133.2003.05337.x. 26905614 .