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ANK2
Ankyrin-2, also known as Ankyrin-B, and Brain ankyrin, is a protein which in humans is encoded by the ''ANK2'' gene. Ankyrin-2 is ubiquitously expressed, but shows high expression in cardiac muscle. Ankyrin-2 plays an essential role in the localization and membrane stabilization of ion transporters and ion channels in cardiomyocytes, as well as in costamere structures. Mutations in ''ANK2'' cause a dominantly-inherited, cardiac arrhythmia syndrome known as long QT syndrome 4 as well as sick sinus syndrome; mutations have also been associated to a lesser degree with hypertrophic cardiomyopathy. Alterations in ankyrin-2 expression levels are observed in human heart failure. Structure Ankyrin-B protein is around 220 kDa, with several isoforms. The ''ANK2'' gene is approximately 560 kb in size and consists of 53 exons on human chromosome 4; ''ANK2'' is also transcriptionally regulated via over 30 alternative splicing events with variable expression of isoforms in cardiac muscle. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ankyrin
Ankyrins are a family of proteins that mediate the attachment of integral membrane proteins to the spectrin-actin based membrane cytoskeleton. Ankyrins have binding sites for the beta subunit of spectrin and at least 12 families of integral membrane proteins. This linkage is required to maintain the integrity of the plasma membranes and to anchor specific ion channels, ion exchangers and ion transporters in the plasma membrane. The name is derived from the Greek word ἄγκυρα (''ankyra'') for "anchor". Structure Ankyrins contain four functional domains: an N-terminal domain that contains 24 tandem ankyrin repeats, a central domain that binds to spectrin, a death domain that binds to proteins involved in apoptosis, and a C-terminal regulatory domain that is highly variable between different ankyrin proteins. Membrane protein recognition The 24 tandem ankyrin repeats are responsible for the recognition of a wide range of membrane proteins. These 24 repeats contain 3 struc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ankyrin Repeat
The ankyrin repeat is a 33-residue motif in proteins consisting of two alpha helices separated by loops, first discovered in signaling proteins in yeast Cdc10 and ''Drosophila'' Notch. Domains consisting of ankyrin tandem repeats mediate protein–protein interactions and are among the most common structural motifs in known proteins. They appear in bacterial, archaeal, and eukaryotic proteins, but are far more common in eukaryotes. Ankyrin repeat proteins, though absent in most viruses, are common among poxviruses. Most proteins that contain the motif have four to six repeats, although its namesake ankyrin contains 24, and the largest known number of repeats is 34, predicted in a protein expressed by ''Giardia lamblia''. Ankyrin repeats typically fold together to form a single, linear solenoid structure called ankyrin repeat domains. These domains are one of the most common protein–protein interaction platforms in nature. They occur in a large number of functionally diverse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ANK3
Ankyrin-3 (ANK-3), also known as ankyrin-G, is a protein from ankyrin family that in humans is encoded by the ''ANK3'' gene. Function The protein encoded by this gene, ankyrin-3 is an immunologically distinct gene product from ankyrins ANK1 and ANK2, and was originally found at the axonal initial segment and nodes of Ranvier of neurons in the central and peripheral nervous systems. Alternatively spliced variants may be expressed in other tissues. Although multiple transcript variants encoding several different isoforms have been found for this gene, the full-length nature of only two have been characterized. Within the nervous system, ankyrin-G is specifically localized to the neuromuscular junction, the axon initial segment and the Nodes of Ranvier. Within the nodes of Ranvier where action potentials are actively propagated, ankyrin-G has long been thought to be the intermediate binding partner to neurofascin and voltage-gated sodium channels. The genetic deletion of ankyrin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long QT Syndrome
Long QT syndrome (LQTS) is a condition affecting repolarization (relaxing) of the heart after a heartbeat, giving rise to an abnormally lengthy QT interval. It results in an increased risk of an irregular heartbeat which can result in fainting, drowning, seizures, or sudden death. These episodes can be triggered by exercise or stress. Some rare forms of LQTS are associated with other symptoms and signs including deafness and periods of muscle weakness. Long QT syndrome may be present at birth or develop later in life. The inherited form may occur by itself or as part of larger genetic disorder. Onset later in life may result from certain medications, low blood potassium, low blood calcium, or heart failure. Medications that are implicated include certain antiarrhythmics, antibiotics, and antipsychotics. LQTS can be diagnosed using an electrocardiogram (EKG) if a corrected QT interval of greater than 480–500 milliseconds is found, but clinical findings, other EKG features, ... [...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 residue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ryanodine Receptor
Ryanodine receptors (RyR for short) form a class of intracellular calcium channels in various forms of excitable animal tissue like muscles and neurons. There are three major isoforms of the ryanodine receptor, which are found in different tissues and participate in different signaling pathways involving calcium release from intracellular organelles. The RYR2 ryanodine receptor isoform is the major cellular mediator of calcium-induced calcium release (CICR) in animal cells. Etymology The ryanodine receptors are named after the plant alkaloid ryanodine which shows a high affinity to them. Isoforms There are multiple isoforms of ryanodine receptors: * RyR1 is primarily expressed in skeletal muscle * RyR2 is primarily expressed in myocardium (heart muscle) * RyR3 is expressed more widely, but especially in the brain. * Non-mammalian vertebrates typically express two RyR isoforms, referred to as RyR-alpha and RyR-beta. * Many invertebrates, including the model organisms Dros ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chimeric Protein
Fusion proteins or chimeric (kī-ˈmir-ik) proteins (literally, made of parts from different sources) are proteins created through the joining of two or more genes that originally coded for separate proteins. Translation of this ''fusion gene'' results in a single or multiple polypeptides with functional properties derived from each of the original proteins. ''Recombinant fusion proteins'' are created artificially by recombinant DNA technology for use in biological research or therapeutics. '' Chimeric'' or ''chimera'' usually designate hybrid proteins made of polypeptides having different functions or physico-chemical patterns. ''Chimeric mutant proteins'' occur naturally when a complex mutation, such as a chromosomal translocation, tandem duplication, or retrotransposition creates a novel coding sequence containing parts of the coding sequences from two different genes. Naturally occurring fusion proteins are commonly found in cancer cells, where they may function as oncoproteins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inositol Trisphosphate Receptor
Inositol trisphosphate receptor (InsP3R) is a membrane glycoprotein complex acting as a Ca2+ channel activated by inositol trisphosphate (InsP3). InsP3R is very diverse among organisms, and is necessary for the control of cellular and physiological processes including cell division, cell proliferation, apoptosis, fertilization, development, behavior, learning and memory. Inositol triphosphate receptor represents a dominant second messenger leading to the release of Ca2+ from intracellular store sites. There is strong evidence suggesting that the InsP3R plays an important role in the conversion of external stimuli to intracellular Ca2+ signals characterized by complex patterns relative to both space and time, such as Ca2+ waves and oscillations. Discovery The InsP3 receptor was first purified from rat cerebellum by neuroscientists Surachai Supattapone and Solomon Snyder at Johns Hopkins University School of Medicine. The cDNA of the InsP3 receptor was first cloned in the la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contractility
Contractility refers to the ability for self-contraction, especially of the muscles or similar active biological tissue *Contractile ring in cytokinesis *Contractile vacuole *Muscle contraction **Myocardial contractility *See contractile cell for an overview of cell types in humans. See also *motility Motility is the ability of an organism to move independently, using metabolic energy. Definitions Motility, the ability of an organism to move independently, using metabolic energy, can be contrasted with sessility, the state of organisms th ... {{SIA Cell movement ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiomyocyte
Cardiac muscle (also called heart muscle, myocardium, cardiomyocytes and cardiac myocytes) is one of three types of vertebrate muscle tissues, with the other two being skeletal muscle and smooth muscle. It is an involuntary, striated muscle that constitutes the main tissue of the wall of the heart. The cardiac muscle (myocardium) forms a thick middle layer between the outer layer of the heart wall (the pericardium) and the inner layer (the endocardium), with blood supplied via the coronary circulation. It is composed of individual cardiac muscle cells joined by intercalated discs, and encased by collagen fibers and other substances that form the extracellular matrix. Cardiac muscle contracts in a similar manner to skeletal muscle, although with some important differences. Electrical stimulation in the form of a cardiac action potential triggers the release of calcium from the cell's internal calcium store, the sarcoplasmic reticulum. The rise in calcium causes the cell's my ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skeletal Muscle
Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscle tissue, and are often known as muscle fibers. The muscle tissue of a skeletal muscle is striated – having a striped appearance due to the arrangement of the sarcomeres. Skeletal muscles are voluntary muscles under the control of the somatic nervous system. The other types of muscle are cardiac muscle which is also striated and smooth muscle which is non-striated; both of these types of muscle tissue are classified as involuntary, or, under the control of the autonomic nervous system. A skeletal muscle contains multiple muscle fascicle, fascicles – bundles of muscle fibers. Each individual fiber, and each muscle is surrounded by a type of connective tissue layer of fascia. Muscle fibers are formed from the cell fusion, fusion of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Half-life
Half-life (symbol ) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable atoms survive. The term is also used more generally to characterize any type of exponential (or, rarely, non-exponential) decay. For example, the medical sciences refer to the biological half-life of drugs and other chemicals in the human body. The converse of half-life (in exponential growth) is doubling time. The original term, ''half-life period'', dating to Ernest Rutherford's discovery of the principle in 1907, was shortened to ''half-life'' in the early 1950s. Rutherford applied the principle of a radioactive element's half-life in studies of age determination of rocks by measuring the decay period of radium to lead-206. Half-life is constant over the lifetime of an exponentially decaying quantity, and it is a characteristic unit for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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