Keratins are a diverse group of structural proteins that form the intermediate filament network responsible for maintaining the structural integrity of keratinocytes. to keratin are considered as important tissue differentiation markers and therefore are an integral aid in diagnostic pathology. The present review discusses the structure of keratin, the various types of keratin and NAK-1 their distribution and the disorders associated with keratinization with special emphasis on the disorders of the oral cavity. A brief note on the clinical significance of keratin is also mentioned. strong class=”kwd-title” Keywords: Keratinization, Keratins, Distribution, Keratinization disorders, Keratin antibodies Intro Epithelia function to safeguard the underlying cells from environmental affects such as for example physical damage, disease, dessication, UV rays, heat loss, also to maintain homeostasis.1 Oral epithelium is classified into three types based on their morphology and specific pattern of differentiation: keratinized stratified squamous epithelium (masticatory mucosa distributed in hard palate and gingiva), non-keratinized stratified squamous epithelium (buccal mucosa, labial mucosa) and specialized free base inhibitor database mucosa (dorsal surface of the tongue).2 An important aspect of stratified squamous epithelia is that the cells undergo a terminal differentiation program that results in the formation of a mechanically resistant and toughened surface composed of cornified cells that are filled with keratin filaments and lack nuclei and cytoplasmic organelles. In these squames, the cell membrane is replaced by a proteinaceous cornified envelope that is covalently cross linked to the keratin filaments, offering a insoluble yet flexible structure that shields the root epithelial cells highly.1 Keratinization, termed as cornification also, is an activity of cytodifferentiation that your keratinocytes undergo when proceeding using their post germinative condition (stratum basale) to finally differentiated, solidified cell filled up with protein, constituting a structurally and functionally specific keratin containing surface area layer such as for example stratum corneum.3 Most of the eukaryotic free base inhibitor database cell is composed of cytoskeleton which is made of three components classified on the basis free base inhibitor database of their diameter and physicochemical properties into microfilaments, intermediate filaments, and microtubules. Microfilaments are the smallest filaments of cytoskeleton with a diameter of 7 nm while microtubules are the largest filamentous structures with a diameter of about 20 nm.4 Intermediate filaments, which serve as a scaffold for the cytoskeleton, are chemically very stable, long and unbranched filaments that aggregate into bundles of varying diameter ranging from 7 to 12 nm. Keratins that form the intermediate filaments are expressed exclusively in the epithelial cells regardless of the germ layer origin of these cells.4 Among the various families and sub-families of intermediate filament proteins, keratin is an important type due to its high molecular diversity. Keratins play a major functional free base inhibitor database role in the integrity and mechanical stability of both the single epithelial cells and via cell to cell contacts of that of the epithelial tissues.5 There are around 30 families of keratin proteins divided into two groups namely acidic and basic which are arranged in pairs. Keratins and certain keratin associated proteins are useful as markers of differentiation because their expression is both region and differentiation specific. Historically, important discoveries in regard to keratin were made in the 1970s. One free base inhibitor database was the obtaining of the spontaneous self assembly and polymerization of keratin filaments from denatured, soluble keratin proteins by dialysis in vitro.6 Different types of keratin were subsequently discovered using various methods. The advances in laboratory diagnostics have also aided in easier identification and characterization of keratin. Currently, the different types of keratin and their associated proteins serve as important markers of differentiation thus aiding in diagnosis of various pathological conditions. The keratin proteins have a.