Poultry feathers consist mainly of the protein keratin, which is rich in β-pleated sheets and consequently resistant to proteolysis. Although many keratinases have been identified, the reasons for their substrate specificity towards β-keratin remain unclear due to difficulties in preparing a soluble feather keratin substrate for use in activity assays. In the present study, we overexpressed Gal...

Feathers are hallmark avian integument appendages, although they were also present on theropods. They are composed of flexible corneous materials made of α- and β-keratins, but their genomic organization and their functional roles in feathers have not been well studied. First, we made an exhaustive search of α- and β-keratin genes in the new chicken genome assembly (Galgal4). Then, using transc...

The expression of intermediate filaments of the keratin- and the vimentin-type was studied in heterokaryons of human fibroblasts and amnion epithelial cells by immunofluorescence microscopy. Fibroblasts and their homokaryons showed a fibrillar, vimentin-specific fluorescence throughout the cytoplasm but were negative when stained for keratin. Amnion epithelial cells and their homokaryons, on t...

XK81A1 is a type I epidermal keratin gene expressed in early developmental stages of Xenopus (Jonas et al. 1985). Fusion of the keratin promoter (-5900 to +26) to a human beta globin gene led to fully epidermis-specific accumulation of human globin mRNA and protein when this DNA was injected into fertilized eggs. Further localization of regulatory sequences was accomplished by injecting marked,...

Abstract Epithelial tissues act as hubs in metabolism and communication and protect the organism against dehydration, infections, pharmacological and physical stress. Keratin intermediate filament proteins are well established as major cytoskeletal players in maintaining epithelial integrity. More recently, an involvement of keratins in growth control and organelle functions has emerged. Disrup...

Defects in protein-folding and -degradation machinery have been identified as a major cause of intracellular protein aggregation and of aggregation-associated diseases. In general, it remains unclear how these aggregates are harmful to normal cellular function. We demonstrate here that, in the developing placenta of the mouse, the absence of the Mrj (Dnajb6) co-chaperone prevents proteasome deg...

Human hair keratin film consisting of fine fibrous and particle structures has been utilized as an alternative device to hair samples. Since application of heat is a well-known factor causing hair damage, the thermal effects on the keratin films and hair samples were examined focusing on color change, morphological observation, protein solubility, and oxidative proteins. The opaque white appear...

This study examines the attributes of keratin intermediate filaments in single, live, nonmotile epithelial cells under steady-state conditions. From their substantive findings, the authors proposed a spatially and temporally defined “keratin cycle” that accounts for the genesis, maturation, and turnover of keratin filaments in the setting of live epithelial cells in culture. I suspect that, jus...

Lorenzo Alibardi (2010) Cornification of the beak of Rana dalmatina tadpoles suggests the presence of basic keratin-associated proteins. Zoological Studies 49(1): 51-63. An ultrastructural, immunocytochemical, and electrophoretic study on keratinocytes formation in the horny beak of tadpoles of the frog Rana dalmatina was conducted. The study showed that hard cornification in amphibians occurs ...

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...