Keratin 6A is one of the 27 different type II keratins expressed in humans. Keratin 6A was the first type II keratin sequence determined.[3] Analysis of the sequence of this keratin together with that of the first type I keratin led to the discovery of the four helical domains in the central rod of keratins.[3] In humans Keratin 6A is encoded by the KRT6Agene.[4][5]
Keratins are the intermediate filament proteins that form a dense meshwork of filaments throughout the cytoplasm of epithelial cells. Keratins form heteropolymers consisting of a type I and a type II keratin. Keratins are generally expressed in particular pairs of type I and type II keratin proteins in a tissue-specific and cellular differentiation-specific manner.
The keratin proteins of epithelial tissues are commonly known as "keratins" or are sometimes referred to as "epithelial keratins" or "cytokeratins". The specialized keratins of hair and nail are known as "hard keratins" or "trichocyte keratins". Trichocytes are the specialized epithelial cells from which hair and nail are composed. Trichocyte keratins are similar in their gene and protein structure to keratins except that they are especially rich in the sulfur-containing amino acid cysteine, which facilitates chemical cross-linking of the assembled hard keratins to form a more structurally resilient material.
Both epithelial keratins and hard keratins can be further subdivided into type I (acidic) keratins and type II (neutral-basic) keratins. The genes for the type I keratins are located in a gene cluster on human chromosome 17q, whereas the genes for type II keratins are located in a cluster on human chromosome 12q (the exception being K18, a type I keratin located in the type II gene cluster).
Keratin 6Aedit
Keratin 6A (protein name K6A; gene name KRT6A), is a type II cytokeratin, one of a number of isoforms of keratin 6 encoded by separate genes located within the type II keratin gene cluster on human chromosome 12q. It is found with keratin 16 and/or keratin 17 in the palm and sole epidermis, the epithelial cells of the nail bed, the filiform papillae of the tongue, the epithelial lining of oral mucosa and esophagus, as well as the hair follicles. This keratin 6 isoform is thought to be the most abundant of the K6 isoforms.
The KRT6A gene consists of 9 exons separated by 8 introns and is located in the type II keratin gene cluster on human chromosome 12q. Keratin 6B and keratin 6C are encoded by the neighbouring genes, which are identical in intron-exon organization to KRT6A and are more than 99% identical in their DNA coding sequences.
Keratin 6A has been shown to have antimicrobial properties, and is the main antimicrobial factor in the eye.[6]
Genetic disordersedit
Mutations in the genes expressing this protein is associated with the PC-K6A subtype of pachyonychia congenita, an inherited disorder of the epithelial tissues in which keratin 6A is expressed, particularly leading to structural abnormalities of the nails, the epidermis of the palms and soles, and oral epithelia.[7][8][9]
Immunohistochemistryedit
The expression of keratin 6A is often tested together with keratin 5, using CK5/6 antibodies, which target both keratin forms.[10]
External linksedit
GeneReviews/NCBI/NIH/UW entry on Pachyonychia Congenita
Referencesedit
^ abcGRCh38: Ensembl release 89: ENSG00000205420 - Ensembl, May 2017
^"Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^ abHanukoglu, I.; Fuchs, E. (Jul 1983). "The cDNA sequence of a Type II cytoskeletal keratin reveals constant and variable structural domains among keratins". Cell. 33 (3): 915–24. doi:10.1016/0092-8674(83)90034-X. PMID 6191871. S2CID 21490380.
^Rosenberg M, Fuchs E, Le Beau MM, Eddy RL, Shows TB (1991). "Three epidermal and one simple epithelial type II keratin genes map to human chromosome 12". Cytogenet. Cell Genet. 57 (1): 33–8. doi:10.1159/000133109. PMID 1713141.
^Schweizer J, Bowden PE, Coulombe PA, Langbein L, Lane EB, Magin TM, Maltais L, Omary MB, Parry DA, Rogers MA, Wright MW (July 2006). "New consensus nomenclature for mammalian keratins". J. Cell Biol. 174 (2): 169–74. doi:10.1083/jcb.200603161. PMC2064177. PMID 16831889.
^"Eye proteins have germ-killing power, could lead to new antimicrobial drugs, study finds". 24 September 2012.
^McLean WH, Rugg EL, Lunny DP, Morley SM, Lane EB, Swensson O, Dopping-Hepenstal PJ, Griffiths WA, Eady RA, Higgins C (March 1995). "Keratin 16 and keratin 17 mutations cause pachyonychia congenita". Nat. Genet. 9 (3): 273–8. doi:10.1038/ng0395-273. PMID 7539673. S2CID 1873772.
^Bowden PE, Haley JL, Kansky A, Rothnagel JA, Jones DO, Turner RJ (July 1995). "Mutation of a type II keratin gene (K6a) in pachyonychia congenita". Nat. Genet. 10 (3): 363–5. doi:10.1038/ng0795-363. PMID 7545493. S2CID 26060130.
^Smith FJ, Jonkman MF, van Goor H, Coleman CM, Covello SP, Uitto J, McLean WH (July 1998). "A mutation in human keratin K6b produces a phenocopy of the K17 disorder pachyonychia congenita type 2". Hum. Mol. Genet. 7 (7): 1143–8. doi:10.1093/hmg/7.7.1143. PMID 9618173.
^Robert Terlević, Semir Vranić. "Cytokeratin 5/6". Topic Completed: 3 June 2019. Revised: 8 December 2019
December 15, 2023
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Keratin 6A is one of the 27 different type II keratins expressed in humans Keratin 6A was the first type II keratin sequence determined 3 Analysis of the sequence of this keratin together with that of the first type I keratin led to the discovery of the four helical domains in the central rod of keratins 3 In humans Keratin 6A is encoded by the KRT6A gene 4 5 KRT6AIdentifiersAliasesKRT6A CK6A CK6C CK6D K6A K6C K6D KRT6C KRT6D PC3 CK 6C CK 6E keratin 6AExternal IDsOMIM 148041 HomoloGene 36182 GeneCards KRT6AGene location Human Chr Chromosome 12 human 1 Band12q13 13Start52 487 176 bp 1 End52 493 257 bp 1 RNA expression patternBgeeHumanMouse ortholog Top expressed inamniotic fluidhair folliclevulvabody of tonguecavity of mouthhuman penisskin of abdomenperiodontal fibervaginapalpebral conjunctivan aMore reference expression dataBioGPSn aGene ontologyMolecular functionstructural constituent of cytoskeleton protein binding structural molecule activityCellular componentkeratin filament extracellular exosome intermediate filament membrane nucleus cytosolBiological processmorphogenesis of an epithelium cell differentiation wound healing positive regulation of cell population proliferation cytoskeleton organization keratinization cornification negative regulation of cytolysis by symbiont of host cells negative regulation of entry of bacterium into host cellSources Amigo QuickGOOrthologsSpeciesHumanMouseEntrez3853n aEnsemblENSG00000205420n aUniProtP02538n aRefSeq mRNA NM 005554n aRefSeq protein NP 005545n aLocation UCSC Chr 12 52 49 52 49 Mbn aPubMed search 2 n aWikidataView Edit Human Contents 1 Keratins 2 Keratin 6A 3 Genetic disorders 4 Immunohistochemistry 5 External links 6 ReferencesKeratins editKeratins are the intermediate filament proteins that form a dense meshwork of filaments throughout the cytoplasm of epithelial cells Keratins form heteropolymers consisting of a type I and a type II keratin Keratins are generally expressed in particular pairs of type I and type II keratin proteins in a tissue specific and cellular differentiation specific manner The keratin proteins of epithelial tissues are commonly known as keratins or are sometimes referred to as epithelial keratins or cytokeratins The specialized keratins of hair and nail are known as hard keratins or trichocyte keratins Trichocytes are the specialized epithelial cells from which hair and nail are composed Trichocyte keratins are similar in their gene and protein structure to keratins except that they are especially rich in the sulfur containing amino acid cysteine which facilitates chemical cross linking of the assembled hard keratins to form a more structurally resilient material Both epithelial keratins and hard keratins can be further subdivided into type I acidic keratins and type II neutral basic keratins The genes for the type I keratins are located in a gene cluster on human chromosome 17q whereas the genes for type II keratins are located in a cluster on human chromosome 12q the exception being K18 a type I keratin located in the type II gene cluster Keratin 6A editKeratin 6A protein name K6A gene name KRT6A is a type II cytokeratin one of a number of isoforms of keratin 6 encoded by separate genes located within the type II keratin gene cluster on human chromosome 12q It is found with keratin 16 and or keratin 17 in the palm and sole epidermis the epithelial cells of the nail bed the filiform papillae of the tongue the epithelial lining of oral mucosa and esophagus as well as the hair follicles This keratin 6 isoform is thought to be the most abundant of the K6 isoforms The KRT6A gene consists of 9 exons separated by 8 introns and is located in the type II keratin gene cluster on human chromosome 12q Keratin 6B and keratin 6C are encoded by the neighbouring genes which are identical in intron exon organization to KRT6A and are more than 99 identical in their DNA coding sequences Keratin 6A has been shown to have antimicrobial properties and is the main antimicrobial factor in the eye 6 Genetic disorders editMutations in the genes expressing this protein is associated with the PC K6A subtype of pachyonychia congenita an inherited disorder of the epithelial tissues in which keratin 6A is expressed particularly leading to structural abnormalities of the nails the epidermis of the palms and soles and oral epithelia 7 8 9 Immunohistochemistry editThe expression of keratin 6A is often tested together with keratin 5 using CK5 6 antibodies which target both keratin forms 10 External links editGeneReviews NCBI NIH UW entry on Pachyonychia CongenitaReferences edit a b c GRCh38 Ensembl release 89 ENSG00000205420 Ensembl May 2017 Human PubMed Reference National Center for Biotechnology Information U S National Library of Medicine a b Hanukoglu I Fuchs E Jul 1983 The cDNA sequence of a Type II cytoskeletal keratin reveals constant and variable structural domains among keratins Cell 33 3 915 24 doi 10 1016 0092 8674 83 90034 X PMID 6191871 S2CID 21490380 Rosenberg M Fuchs E Le Beau MM Eddy RL Shows TB 1991 Three epidermal and one simple epithelial type II keratin genes map to human chromosome 12 Cytogenet Cell Genet 57 1 33 8 doi 10 1159 000133109 PMID 1713141 Schweizer J Bowden PE Coulombe PA Langbein L Lane EB Magin TM Maltais L Omary MB Parry DA Rogers MA Wright MW July 2006 New consensus nomenclature for mammalian keratins J Cell Biol 174 2 169 74 doi 10 1083 jcb 200603161 PMC 2064177 PMID 16831889 Eye proteins have germ killing power could lead to new antimicrobial drugs study finds 24 September 2012 McLean WH Rugg EL Lunny DP Morley SM Lane EB Swensson O Dopping Hepenstal PJ Griffiths WA Eady RA Higgins C March 1995 Keratin 16 and keratin 17 mutations cause pachyonychia congenita Nat Genet 9 3 273 8 doi 10 1038 ng0395 273 PMID 7539673 S2CID 1873772 Bowden PE Haley JL Kansky A Rothnagel JA Jones DO Turner RJ July 1995 Mutation of a type II keratin gene K6a in pachyonychia congenita Nat Genet 10 3 363 5 doi 10 1038 ng0795 363 PMID 7545493 S2CID 26060130 Smith FJ Jonkman MF van Goor H Coleman CM Covello SP Uitto J McLean WH July 1998 A mutation in human keratin K6b produces a phenocopy of the K17 disorder pachyonychia congenita type 2 Hum Mol Genet 7 7 1143 8 doi 10 1093 hmg 7 7 1143 PMID 9618173 Robert Terlevic Semir Vranic Cytokeratin 5 6 Topic Completed 3 June 2019 Revised 8 December 2019 Retrieved from https en wikipedia org w index php title Keratin 6A amp oldid 1045070084, wikipedia, wiki, book, books, library,
