 keratin 6a is one of the 27 different type ii keratins expressed in humans. keratin 6a was the first type ii keratin sequence determined. 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. in humans keratin 6a is encoded by the krt6a gene. == keratins == 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 6a == k
Human_proteins Keratins