The term 'keratin' is generally accepted to refer to the epithelial keratins of soft and hard epithelial tissues such as: skin, cornea, hair and nail. Since their initial characterization, the total number of mammalian keratins has increased to 54, including 28 type I and 26 type II keratins. Inherited defects that weaken the keratin load-bearing cytoskeleton produce phenotypes characterized by...

The 8-nm keratin filament is a major component of the cytoskeleton of epithelial cells and epithelial-derived cancers (carcinomas). Recently, it has been shown that the pattern of keratins produced by an esophageal epithelial cell undergoes change upon malignant transformation. In order to evaluate the potential importance of these differences in providing improved diagnostic techniques for pat...

When compared to normal esophageal epithelium, marked alterations in keratin protein and cross-linked envelope expression were found in human esophageal carcinomas. Examination of the pattern of keratin proteins extracted from either several primary esophageal tumors or carcinomas xenotransplanted in nude mice revealed a dramatic reduction in the amount of keratin protein, especially in the Mr ...

Cytokeratins in taste buds were immunocytochemically evaluated with monoclonal antibodies. In each of six different epithelial sites in the rat oral cavity, intragemmal cells of taste buds were immunoreactive for keratin polypeptides 8, 18, and 19, as well as for keratin 7, which has not been previously reported in taste buds. Keratin-18-like immunoreactivity was present in fewer than half of t...

We present the complete nucleotide and deduced amino acid sequences of a mouse epidermal keratin subunit of 60,000 Da. The keratin possesses a central alpha-helical domain of four tracts (termed 1A, 1B, 2A, and 2B) that can form coiled-coils, interspersed by short linker sequences, and has non-alpha-helical terminal domains. This pattern of secondary structure is emerging as common to all inter...

Tonofilament protein from newborn rat epidermis was found to be antigenically related to mouse keratins. Tonofilament protein, like keratins, could be extracted with 8 M urea in Tris buffer. The yield was enhanced by the presence of dithiothreitol. A higher molecular weight (64,000 dalton) protein antigenically cross-reacting with tonofilament protein but with a slightly different amino acid co...

Keratin intermediate filament proteins form the major cytoskeleton in all embryonic and adultepithelia. Increasing evidence suggests that keratins, besides their primary cytoskeletal function, canact as scaffolds which locally regulate cell growth and survival in epithelial cells. Many of thesefunctions, however, are not understood in full, owing to keratin redundancy. We have recen...

Keratins K8 and K18 are the major components of the intermediate-filament cytoskeleton of simple epithelia. Increased levels of these keratins have been correlated with various tumor cell characteristics, including progression to malignancy, invasive behavior, and drug sensitivity, although a role for K8/K18 in tumorigenesis has not yet been demonstrated. To examine the function of these kerati...

Avian integumentary organs include feathers, scales, claws, and beaks. They cover the body surface and play various functions to help adapt birds to diverse environments. These keratinized structures are mainly composed of corneous materials made of α-keratins, which exist in all vertebrates, and β-keratins, which only exist in birds and reptiles. Here, members of the keratin gene families were...