Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q07644 (polypeptide)
 72,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Components of desmosomes, filaments, and keratohyaline granules were studied by electron microscope and biochemical methods to clarify their role in the stabilization and keratinization of the epidermis. Isolated desmosomes are composed of 76% protein, 17% carbohydrate, and 10% lipid. The bulk of protein consists of a "spectrin"-like fibrous protein, presumably present in the plaque, and of glycoproteins in the desmosomal interspace. The main component of filaments, prekeratin, is a low-sulfur alpha-protein composed of a pair of three-chain subunits with non-alpha-helical segments separated by 200 A-long alpha-helical regions. The major component of isolated keratohyaline granules, the amorphous particulate material, is formed by a high-sulfur protein with a single-type of polypeptide chain. Polypeptide chains comparable to those found in prekeratin and keratohyaline granules were recovered from extracts of horny cells. Within the living part of the epidermis, filaments hypothetically form a cytoskeletal system which is anchored to desmosomes by a filamentous plaque protein. Glycoproteins are involved in the formation of strong junctions between the cells which enable the living part of the epidermis to respond as a whole to mechanical stress. The stratum corneum is stabilized by a similar system in a consolidated state which is less extensible. Horny cells are enveloped by a thickened membrane and the interfilamentous spaces are filled with various proteins including the sulfur-rich amorphous protein found in keratohyaline granules.
J Invest Dermatol 1975 Jul
PMID:Desmosomes, filaments, and keratohyaline granules: their role in the stabilization and keratinization of the epidermis. 5 Mar 84

The Merkel cell, a neural crest migrant to the skin, possesses a characteristic intranuclear rodlet, cytoplasmic membrane-bound granules, and horn projections and is usually associated with nerve terminations. It is also associated with all types of known organizations of sensory nerve endings in the skin and possesses characteristic enzyme reactions in relation to the ending. The Merkel cell is found in the skin and the oral mucous membranes, and similar cells are observed in the taste buds and pulmonary tissue. A comparison between the Merkel cell and the APUD cell system of polypeptide hormone and amine-producing cells reveals many structural and chemical similarities.
J Invest Dermatol 1977 Jul
PMID:The Merkel cell system and a comparison between it and the neurosecretory or APUD cell system. 6 82

The fibrous protein of stratum corneum was isolated from a patient with bullous congenital ichthyosiform erythroderma (BCIE), and its properties characterized using electron microscopy, amino acid analysis and SDS gel electrophoresis. Results were compared with the characteristics of the fibrous protein isolated from stratum corneum of normal controls. From 900 mg (dry weight) of stratum corneum, 68 mg of fibrous protein was obtained from the patient, while 178 mg was obtained from the normal control. Structural differences were observed with electron microscopy and chemical differences, were shown in the ratio of several amino acids. On SDS electrophoresis, the 55,000 dalton constituent of normal fibrous protein could not be identified in the fibrous protein from this patient. These results suggest that an alteration of the polypeptide composition of fibrous protein from this patient with BCIE occurred, and this alteration induced the morphological and clinical features of this dominant genetic keratinization disorder.
Arch Dermatol Res 1979 Oct
PMID:Abnormal fibrous protein isolated from the stratum corneum of a patient with bullous congenital ichthyosiform erythroderma (BCIE). 16 Jul 75

Neoplasms of pancreatic islet cells that produce widely divergent clinical syndromes cannot be distinguished from one another by conventional microscopy. Differentiation among these tumors by electron microscopy is possible in some cases only. Coordinated clinical evaluation, histochemical and ultrastructural studies, and assay of serum and neoplastic tissue for various polypeptide hormones afford the best characterization of these neoplasms.
J Dermatol Surg Oncol 1978 Oct
PMID:Electron microscopy of neoplasms of pancreatic islet cells. 21 61

Enzymes known as transglutaminases mediate cross-linking of polypeptide chains by epsilon-(gamma-glutamyl) lysine bonds. Such bonds stabilize structural proteins of many tissues; transglutaminases specific for these tissues have been identified. A calcium- and sulfhydryl-dependent transglutaminase with a molecular weight of 55,000 has been purified from bovine snout epidermis and used to elicit a specific antiserum to the enzyme. Sites of epidermal transglutaminase activity have been localized in the cytoplasm of upper malpighian and granular cells by two complementary methods. When thin-tissue sections were incubated with a fluorescent lysine analog(dansyl cadaverine) and calcium, tissue acceptor sites became fluorescent. Localization was confirmed by fluorescein-conjugated antibody labeling of the enzyme in situ. These observations indicate that epidermal transglutaminase cross-links epidermal proteins during the final stages of keratinization.
J Invest Dermatol 1975 Jul
PMID:Keratin cross-linking and epidermal transglutaminase. A review with observations on the histochemical and immunochemical localization of the enzyme. 23 69

The elastic fibers present in various connective tissues of the body are responsible for physiologic elasticity of the organs. These fibers consist of 2 distinct components, elastin and the elastic fiber microfibrils. Controlled synthesis and balanced interaction of these 2 components are essential for normal fibrillogenesis. The intracellular biosynthesis of elastin by connective tissue cells, such as smooth muscle cells, involves assembly of the polypeptide chains on the membrane-bound ribosomes, hydroxylation of some prolyl residues to hydroxyproline, and secretion of the polypeptides packaged in Golgi vacuoles. In the extracellular space the elastin molecules assemble into fiber structures which are stabilized by the synthesis of complex covalent cross-links, desmosines. Recently, aberrations in the structure or metabolism of elastin have been detected in a variety of heritable and acquired diseases affecting skin and other connective tissues. These conditions include pseudoxanthoma elasticum, cutis laxa, and elastosis perforans serpiginosa, as well as arteriosclerosis and other degenerative changes of the vascular connective tissues.
J Invest Dermatol 1979 Jan
PMID:Biochemistry of the elastic fibers in normal connective tissues and its alterations in diseases. 36 54

This study was designed to chemically characterize the principal structural proteins of psoriatic scales. Cornified cells were obtained from 40 patients with psoriasis, 21 patients with other scaly diseases, and 13 normal individuals. Cells were washed with Tris-HCl buffer and incubated in 8 M urea containing 2-mercaptoethanol (pH 9.0) at 30 degrees C for 7 hr. Extracted proteins were subjected to SDS polyacrylamide gel electrophoresis and protein patterns from normal and diseased scales were compared. The 67,000 dalton constituent of normal cornified cells could not be identified in protein from psoriatic scale and instead, a pair of polypeptides of approximately 54,000 and 57,000 daltons appeared. These extra bands were not found in protein extractions from other skin diseases, uninvolved skin of psoriasis patients, or normal skin. In order to analyze further normal and psoriatic scale proteins, the immunoreaction of rabbit antisera to human 67,000 dalton polypeptide with extracted psoriasis protein and with frozen biopsy sections, was studied using immunoprecipitation tests and indirect immunofluorescence microscopy. Both techniques demonstrated the existence of the 67,000 dalton protein in psoriasis, but as a minor component. These results indicate that additional unique urea mercaptoethanol soluble proteins are formed in psoriatic lesions, and this unusual protein synthesis may reflect the morphological changes in this disease.
J Invest Dermatol 1978 Jan
PMID:Two tris urea mercaptoethanol extractable polypeptides found uniquely in scales of patients with psoriasis. 61 78

Prekeratin has been isolated from human epidermis using the method of Matoltsy for bovine nose epidermis. Analysis by sedimentation equilibrium indicates that human prekeratin is heterogeneous in solution. The molecular weight range is from about 200 X 10(3) to at least 2 X 10(6). Polyacrylamide gel electrophoresis shows three polypeptide chains of molecular weights 65,000 60,000 and 58,000. A lower than average ratio of polar/apolar amino acid residues suggests that hydrophobic interactions are important for stability.
Br J Dermatol 1978 Feb
PMID:Precursor keratin protein from human epidermis. 62 71

The fibrous proteins of the malpighian layer of human epidermis (prekeratin) have been isolated with citrate buffer, pH 2.65, and shown to consist of 7 polypeptide chains varying in molecular weight from 45,000 daltons to 67,000. Some variation in the number and amount of the components was observed in prekeratin prepared from the epidermis of different individuals. The fibrous proteins of the stratum corneum were isolated with Tris buffer, pH 9.0, containing 6 M urea and 0.1 M mercapto-ethanol and were found to have a pattern similar to prekeratin but not identical to it. However, fibrous protein isolated from the superficial layers of the stratum showed a considerably different pattern indicating that there was post-translational modification of the protein in the late stages of keratinization. These data show that human keratin has the same heterogeneity which was observed previously in cow epidermis. This was further confirmed by studying the polypeptide chain content of prekeratin from a large number of lesions showing benign epidermal hyperplasia, where considerable variation in composition was observed.
J Invest Dermatol 1978 Aug
PMID:Fibrous protein of human epidermis. 68 84

This report describes the preparation and detection of antibodies to chemically unmodified prekeratin and stratum corneum proteins of cow and human epidermis. The antibodies are specific for epidermal fibrous proteins and do not cross-react with those of hair and nail which have the same molecular configuration but but distinctive physical and chemical properties. The antibodies did cross-react with epidermal fibrous proteins from a number of other vertebrate sources indicating an immunologic relationship among epidermal proteins whose polypeptide compositions and amino acid contents are somewhat dissimilar. Both antibodies give intense immunofluorescence localized to the malpighian layers but not to the stratum corneum. The antigenic sites in the native configuration of the stratum corneum layer may be buried, since denatured stratum corneum proteins react readily with the antibody. These antibodies have permitted the first detection of a form of keratin whose solubility properties are quite different from either prekeratin or stratum corneum proteins.
J Invest Dermatol 1976 Oct
PMID:Immunology of epidermal fibrous proteins. 82 69


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