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CLDN4
Claudin 4, also known as CLDN4, is a protein which in humans is encoded by the ''CLDN4'' gene. It belongs to the group of claudins. This gene encodes an integral membrane protein, which belongs to the claudin family. The protein is a component of tight junction strands and may play a role in internal organ development and function during pre- and postnatal life. This gene is deleted in Williams-Beuren syndrome, a neurodevelopmental disorder affecting multiple systems. Claudin 4 can also be used as a marker for distinguishing malignant mesothelioma from lung cancer and uterine serous carcinoma. As a pancreatic cancer Pancreatic cancer arises when cells in the pancreas, a glandular organ behind the stomach, begin to multiply out of control and form a mass. These cancerous cells have the ability to invade other parts of the body. A number of types of pancr ... marker in cell-blocks of effusion specimens, it has also been found to have a superior performance to BerEp4 staini ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Claudin
Claudins are a family of proteins which, along with occludin, are the most important components of the tight junctions ( zonulae occludentes). Tight junctions establish the paracellular barrier that controls the flow of molecules in the intercellular space between the cells of an epithelium. They have four transmembrane domains, with the N-terminus and the C-terminus in the cytoplasm. Structure Claudins are small (20–24/27 kilodalton (kDa)) transmembrane proteins which are found in many organisms, ranging from nematodes to human beings. They all have a very similar structure. Claudins span the cellular membrane 4 times, with the N-terminal end and the C-terminal end both located in the cytoplasm, and two extracellular loops which show the highest degree of conservation. Claudins have both cis and trans interactions between cell membranes. Cis-interactions is when claudins on the same membrane interact, one way they interact is by transmembrane domain having molecular inte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Williams-Beuren Syndrome
Williams syndrome (WS) is a genetic disorder that affects many parts of the body. Facial features frequently include a broad forehead, underdeveloped chin, short nose, and full cheeks. Mild to moderate intellectual disability is observed in people with WS, with particular challenges with visual spatial tasks such as drawing. Verbal skills are relatively unaffected. Many people with WS have an outgoing personality, an openness to engaging with other people, and a happy disposition. Medical issues with teeth, heart problems (especially supravalvular aortic stenosis), and periods of high blood calcium are common. Williams syndrome is caused by a genetic abnormality, specifically a deletion of about 27 genes from the long arm of one of the two chromosome 7s. Typically, this occurs as a random event during the formation of the egg or sperm from which a person develops. In a small number of cases, it is inherited from an affected parent in an autosomal dominant manner. The dif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integral Membrane Protein
An integral, or intrinsic, membrane protein (IMP) is a type of membrane protein that is permanently attached to the biological membrane. All ''transmembrane proteins'' are IMPs, but not all IMPs are transmembrane proteins. IMPs comprise a significant fraction of the proteins encoded in an organism's genome. Proteins that cross the membrane are surrounded by annular lipids, which are defined as lipids that are in direct contact with a membrane protein. Such proteins can only be separated from the membranes by using detergents, nonpolar solvents, or sometimes denaturing agents. Structure Three-dimensional structures of ~160 different integral membrane proteins have been determined at atomic resolution by X-ray crystallography or nuclear magnetic resonance spectroscopy. They are challenging subjects for study owing to the difficulties associated with extraction and crystallization. In addition, structures of many water- soluble protein domains of IMPs are available in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tight Junction
Tight junctions, also known as occluding junctions or ''zonulae occludentes'' (singular, ''zonula occludens''), are multiprotein junctional complexes whose canonical function is to prevent leakage of solutes and water and seals between the epithelial cells. They also play a critical role maintaining the structure and permeability of endothelial cells. Tight junctions may also serve as leaky pathways by forming selective channels for small cations, anions, or water. The corresponding junctions that occur in invertebrates are septate junctions. Structure Tight junctions are composed of a branching network of sealing strands, each strand acting independently from the others. Therefore, the efficiency of the junction in preventing ion passage increases exponentially with the number of strands. Each strand is formed from a row of transmembrane proteins embedded in both plasma membranes, with extracellular domains joining one another directly. There are at least 40 different protei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesothelioma
Mesothelioma is a type of cancer that develops from the thin layer of tissue that covers many of the internal organs (known as the mesothelium). The most common area affected is the lining of the lungs and chest wall. Less commonly the lining of the abdomen and rarely the sac surrounding the heart, or the sac surrounding the testis may be affected. Signs and symptoms of mesothelioma may include shortness of breath due to fluid around the lung, a swollen abdomen, chest wall pain, cough, feeling tired, and weight loss. These symptoms typically come on slowly. More than 80% of mesothelioma cases are caused by exposure to asbestos. The greater the exposure the greater the risk. As of 2013, about 125 million people worldwide have been exposed to asbestos at work. High rates of disease occur in people who mine asbestos, produce products from asbestos, work with asbestos products, live with asbestos workers, or work in buildings containing asbestos. Asbestos exposure and the ons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lung Cancer
Lung cancer, also known as lung carcinoma (since about 98–99% of all lung cancers are carcinomas), is a malignant lung tumor characterized by uncontrolled cell growth in tissues of the lung. Lung carcinomas derive from transformed, malignant cells that originate as epithelial cells, or from tissues composed of epithelial cells. Other lung cancers, such as the rare sarcomas of the lung, are generated by the malignant transformation of connective tissues (i.e. nerve, fat, muscle, bone), which arise from mesenchymal cells. Lymphomas and melanomas (from lymphoid and melanocyte cell lineages) can also rarely result in lung cancer. In time, this uncontrolled growth can metastasize (spreading beyond the lung) either by direct extension, by entering the lymphatic circulation, or via hematogenous, bloodborne spread – into nearby tissue or other, more distant parts of the body. Most cancers that originate from within the lungs, known as primary lung cancers, are carcinomas. The t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uterine Serous Carcinoma
Uterine serous carcinoma is a malignant form of serous tumor that originates in the uterus. It is an uncommon form of endometrial cancer that typically arises in postmenopausal women. It is typically diagnosed on endometrial biopsy, prompted by post-menopausal bleeding. Unlike the more common low-grade endometrioid endometrial adenocarcinoma, uterine serous carcinoma does not develop from endometrial hyperplasia and is not hormone-sensitive. It arises in the setting of endometrial atrophy and is classified as a type II endometrial cancer. Cause Initially there is a precursor lesion called serous endometrial intraepithelial carcinoma. Mutation is found in TP53 gene which is a tumor suppressor gene even in precursor lesion suggesting early involvement of this gene. Also many missense mutation and mutation in PI3K and PP2A genes are involved which also contribute to this tumor. Diagnosis The lesion is found in patients who present typically with abnormal or postmenopausal ble ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pancreatic Cancer
Pancreatic cancer arises when cells in the pancreas, a glandular organ behind the stomach, begin to multiply out of control and form a mass. These cancerous cells have the ability to invade other parts of the body. A number of types of pancreatic cancer are known. The most common, pancreatic adenocarcinoma, accounts for about 90% of cases, and the term "pancreatic cancer" is sometimes used to refer only to that type. These adenocarcinomas start within the part of the pancreas that makes digestive enzymes. Several other types of cancer, which collectively represent the majority of the non-adenocarcinomas, can also arise from these cells. About 1–2% of cases of pancreatic cancer are neuroendocrine tumors, which arise from the hormone-producing cells of the pancreas. These are generally less aggressive than pancreatic adenocarcinoma. Signs and symptoms of the most-common form of pancreatic cancer may include yellow skin, abdominal or back pain, unexplained weight loss, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
