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Cytokeratins
Cytokeratins are keratin proteins found in the intracytoplasmic cytoskeleton of epithelial tissue. They are an important component of intermediate filaments, which help cells resist mechanical stress. Expression of these cytokeratins within epithelial cells is largely specific to particular organs or tissues. Thus they are used clinically to identify the cell of origin of various human tumors. Naming The term ''cytokeratin'' began to be used in the late 1970s, when the protein subunits of keratin intermediate filaments inside cells were first being identified and characterized. In 2006 a new systematic nomenclature for mammalian keratins was created, and the proteins previously called ''cytokeratins'' are simply called ''keratins'' (human epithelial category). For example, cytokeratin-4 (CK-4) has been renamed keratin-4 (K4). However, they are still commonly referred to as cytokeratins in clinical practice. Types There are two categories of cytokeratins: the acidic type I cy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type II Cytokeratin
Type II keratins (or Type II cytokeratins) constitutes the Type II intermediate filaments (IFs) of the intracytoplasmatic cytoskeleton, which is present in all mammalian epithelial cells. The type 2 cytokeratins consist of basic or neutral, high molecular weight proteins which in vivo are arranged in pairs of heterotypic Type I and Type II keratin chains, coexpressed during differentiation of simple and stratified epithelial tissues. It has been seen that Type II Keratins are developed before Type 1 keratins during human embryonic development. Type II cytokeratins are encoded on chromosome 12q and encompasses: CK1, CK2, CK3, CK4, CK5, CK6, CK7 and CK8. Their molecular weight ranges from 52 kDa (CK8) to 67 kDa (CK18). Overall, keratin type 2 plays a crucial role in maintaining the strength and integrity of the skin, hair, and nails. Mutations in keratin genes can lead to various genetic disorders that affect these tissues, such as epidermolysis bullosa simplex, a rare conditi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keratin 8
Keratin, type II cytoskeletal 8 also known as cytokeratin-8 (CK-8) or keratin-8 (K8) is a keratin protein that is encoded in humans by the ''KRT8'' gene. It is often paired with keratin 18. Utility as an immunohistochemical stain Antibodies to CK8 (e.g. CAM 5.2) can be used to differentiate lobular carcinoma of the breast from ductal carcinoma of the breast. CAM 5.2, an antibody that reacts with an epitope found on both CK8 and CK18, is used in immunohistochemistry to demonstrate certain forms of cancer. In normal tissue, it reacts mainly with secretory epithelia, but not with squamous epithelium, such as that found in the skin, cervix, and esophagus. However, it also reacts with a range of malignant cells, including those derived from secretory epithelia, but also some squamous carcinomata, such as spindle cell carcinoma. It is considered useful in identifying microscopic metastases of breast carcinoma in lymph nodes, and in distinguishing Paget's disease from malignant mel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keratin 7
Keratin, type II cytoskeletal 7 also known as cytokeratin-7 (CK-7) or keratin-7 (K7) or sarcolectin (SCL) is a protein that in humans is encoded by the ''KRT7'' gene. Keratin 7 is a type II keratin. It is specifically expressed in the simple epithelia lining the cavities of the internal organs and in the gland ducts and blood vessels. Function Keratin-7 is a member of the keratin gene family. The type II cytokeratins consist of basic or neutral proteins which are arranged in pairs of heterotypic keratin chains coexpressed during differentiation of simple and stratified epithelial tissues. This type II cytokeratin is specifically expressed in the simple epithelia lining the cavities of the internal organs and in the gland ducts and blood vessels. The genes encoding the type II cytokeratins are clustered in a region of chromosome 12q12-q13. Alternative splicing may result in several transcript variants; however, not all variants have been fully described. Keratin-7 is found in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keratin 17
Keratin, type I cytoskeletal 17 is a protein that in humans is encoded by the ''KRT17'' gene. Keratin 17 is a type I cytokeratin. It is found in nail beds, hair follicles, sebaceous glands, and other epidermal appendages. Mutations in the gene encoding this protein lead to PC-K17 (previously known as Jackson-Lawler) type pachyonychia congenita and steatocystoma multiplex Steatocystoma multiplex is a benign, autosomal dominant congenital condition resulting in multiple cysts on a person's body. Steatocystoma simplex is the solitary counterpart to steatocystoma multiplex. In steatocystoma multiplex, the tendency to .... Interactions Keratin 17 has been shown to interact with CCDC85B. References Further reading * * * * * * * * * * * * * * * * * External links GeneReviews/NCBI/NIH/UW entry on Pachyonychia Congenita Keratins {{gene-17-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keratin 4
Keratin, type I cytoskeletal 4 also known as cytokeratin-4 (CK-4) or keratin-4 (K4) is a protein that in humans is encoded by the ''KRT4'' gene. Keratin 4 is a type II cytokeratin. It is specifically found in differentiated layers of the mucosal and esophageal epithelia together with keratin 13. Mutations in the genes encoding this protein have been associated with White Sponge Nevus, characterized by oral, esophageal, and anal leukoplakia Oral leukoplakia is a potentially malignant disorder affecting the oral mucosa. It is defined as "essentially an oral mucosal white/gray lesion that cannot be considered as any other definable lesion." Oral leukoplakia is a gray patch or plaque th .... References Further reading * * * * * * * * * * * * * * * * * Keratins {{Gene-12-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keratin 15
Keratin 15 is a protein that in humans is encoded by the ''KRT15'' gene. It has also been referred to as cytokeratin 15, K1CO and KRTB. Keratin 15 is a type I cytokeratin. It is well-expressed in the basal layer of stratified epithelium (other), complex epithelia. However, acral keratinocytes express little to no keratin 15. References Further reading * * * * * * * * * * * * * * * Keratins {{Gene-17-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keratin 6
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. Keratin family 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 keratin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keratin 5
Keratin 5, also known as KRT5, K5, or CK5, is a protein that is encoded in humans by the ''KRT5'' gene. It protein dimer, dimerizes with keratin 14 and forms the intermediate filaments (IF) that make up the cytoskeleton of Stratum basale, basal epithelial cells. This protein is involved in several diseases including epidermolysis bullosa simplex and breast and lung cancers. Structure Keratin 5, like other members of the keratin family, is an intermediate filament protein. These polypeptides are characterized by a 310 residue central rod domain that consists of four alpha helix segments (helix 1A, 1B, 2A, and 2B) connected by three short linker regions (L1, L1-2, and L2). The ends of the central rod domain, which are called the helix initiation motif (HIM) and the helix termination motif (HTM), are highly conserved. They are especially important for Alpha helix#Stability, helix stabilization, heterodimer formation, and filament formation. Lying on either side of the central rod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type I Cytokeratin
Type I keratins (or Type I cytokeratins) are cytokeratins that constitute the Type I intermediate filaments (IFs) of the intracytoplasmatic cytoskeleton, which is present in all mammalian epithelial cells. Most of the type I keratins consist of acidic, low molecular weight proteins which in vivo are arranged in pairs of heterotypic Type I and Type II keratin chains, coexpressed during differentiation of simple and stratified epithelial tissues. Type I keratins are encoded on chromosome 17q and encompasses: K9, K10, K11, K12, K13, K14, K15, K16, K17, K18, K19 and K20. Their molecular weight ranges from 40 kDa (K19) to 64 kDa (K9). See also *Type II keratin Type II keratins (or Type II cytokeratins) constitutes the Type II intermediate filaments (IFs) of the intracytoplasmatic cytoskeleton, which is present in all mammalian epithelial cells. The type 2 cytokeratins consist of basic or neutral, high mo ... External links * Proteopedia page on keratins Keratins {{Fibrous prote ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keratin
Keratin () is one of a family of structural fibrous proteins also known as ''scleroproteins''. It is the key structural material making up Scale (anatomy), scales, hair, Nail (anatomy), nails, feathers, horn (anatomy), horns, claws, Hoof, hooves, and the outer layer of skin in vertebrates. Keratin also protects epithelial cells from damage or stress. Keratin is extremely insoluble in water and organic solvents. Keratin monomers assemble into bundles to form intermediate filaments, which are tough and form strong mineralization (biology), unmineralized epidermal appendages found in reptiles, birds, amphibians, and mammals. Excessive keratinization participate in fortification of certain tissues such as in horns of cattle and rhinos, and armadillos' osteoderm. The only other biology, biological matter known to approximate the toughness of keratinized tissue is chitin. Keratin comes in two types: the primitive, softer forms found in all vertebrates and the harder, derived forms fou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keratin 13
Keratin 13 (or cytokeratin 13) is a protein that in humans is encoded by the ''KRT13'' gene. Keratin 13 is a type I cytokeratin, it is paired with keratin 4 Keratin, type I cytoskeletal 4 also known as cytokeratin-4 (CK-4) or keratin-4 (K4) is a protein that in humans is encoded by the ''KRT4'' gene. Keratin 4 is a type II cytokeratin. It is specifically found in differentiated layers of the mucosal a ... and found in the suprabasal layers of non-cornified stratified epithelia. Mutations in the gene encoding this protein and keratin 4 have been associated with the autosomal dominant disorder White Sponge Nevus. References Further reading * * * * * * * * * * * * * * * * * * Keratins {{Gene-17-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keratin 16
Keratin 16 is a protein that in humans is encoded by the ''KRT16'' gene. Keratin 16 is a type I cytokeratin. It is paired with keratin 6 in a number of epithelial tissues, including nail bed, esophagus, tongue, and hair follicle The hair follicle is an organ found in mammalian skin. It resides in the dermal layer of the skin and is made up of 20 different cell types, each with distinct functions. The hair follicle regulates hair growth via a complex interaction betwee ...s. Mutations in the gene encoding this protein are associated with the genetic skin disorders including pachyonychia congenita, non-epidermolytic palmoplantar keratoderma and unilateral palmoplantar verrucous nevus. References External links GeneReviews/NCBI/NIH/UW entry on Pachyonychia Congenita Further reading * * * * * * * * * * * * * * * * * * Keratins {{Gene-17-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
