Keratin 6C(protein name K6C; gene nameKRT6C), is a type II cytokeratin,one of a number ofisoformsofkeratin 6encoded by separate genes located within the type II keratin gene cluster on humanchromosome 12q.This gene was uncovered recently by theHuman Genome Projectand its expression patterns in humans remains unknown.
Keratinsare theintermediate filamentproteins that form a dense meshwork of filaments throughout thecytoplasmofepithelialcells.[5]Keratins form heteropolymersconsisting 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 atissue-specific andcellular 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 ofhairandnailare known as "hard keratins" or "trichocytekeratins ". 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 thesulfur-containingamino acidcysteine, 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 humanchromosome 17q,whereas the genes for type II keratins are located in a cluster on humanchromosome 12q(the exception being K18, a type I keratin located in the type II gene cluster).
Like the closely relatedKRT6AandKRT6Bgenes, theKRT6Cgene consists of 9exonsseparated by 8intronsand is located in the type II keratin gene cluster on humanchromosome12q.Keratin 6Aandkeratin 6Bare encoded by the neighbouring genes, which are identical inintron-exonorganization toKRT6Cand are more than 99% identical in theirDNAcoding sequences.
Mutations in K6C have been identified as being able to cause diffuse and focal palmoplantar keratodermas.[6][7][8]This has been identified as a form ofPachyonychia congenita.[9][10]
^O'Toole EA, Kaspar RL, Sprecher E, Schwartz ME, Rittié L (2014). "Pachyonychia congenita cornered: report on the 11th Annual International Pachyonychia Congenita Consortium Meeting".Br. J. Dermatol.171(5): 974–7.doi:10.1111/bjd.13341.hdl:2027.42/109650.PMID25124823.S2CID1481875.
