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Cardiac Sodium Channel
Sodium channel protein type 5 subunit alpha, also known as NaV1.5 is an integral membrane protein and tetrodotoxin-resistant voltage-gated sodium channel subunit. NaV1.5 is found primarily in cardiac muscle, where it mediates the fast influx of Na+-ions (INa) across the cell membrane, resulting in the fast depolarization phase of the cardiac action potential. As such, it plays a major role in electrical conduction system of the heart, impulse propagation through the heart. A vast number of cardiac diseases is associated with mutations in NaV1.5 (see paragraph #Genetics, genetics). ''SCN5A'' is the gene that encodes the cardiac sodium channel NaV1.5. Gene structure SCN5A is a highly conserved gene located on human chromosome 3, where it spans more than 100 kb. The gene consists of 28 exons, of which exon 1 and in part exon 2 form the 5' untranslated region (Five prime untranslated region, 5’UTR) and exon 28 the 3' untranslated region (Three prime untranslated region, 3’UTR) o ... [...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 Prote ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epicardium
The pericardium, also called pericardial sac, is a double-walled sac containing the heart and the roots of the great vessels. It has two layers, an outer layer made of strong connective tissue (fibrous pericardium), and an inner layer made of serous membrane (serous pericardium). It encloses the pericardial cavity, which contains pericardial fluid, and defines the middle mediastinum. It separates the heart from interference of other structures, protects it against infection and blunt trauma, and lubricates the heart's movements. The English name originates from the Ancient Greek prefix "''peri-''" (περί; "around") and the suffix "''-cardion''" (κάρδιον; "heart"). Anatomy The pericardium is a tough fibroelastic sac which covers the heart from all sides except at the cardiac root (where the great vessels join the heart) and the bottom (where only the serous pericardium exists to cover the upper surface of the central tendon of diaphragm). The fibrous pericardium ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lev's Disease
Lev's disease is an acquired complete heart block due to idiopathic fibrosis and calcification of the electrical conduction system of the heart. Lev's disease is most commonly seen in the elderly, and is often described as senile degeneration of the conduction system. One form has been associated with SCN5A. Presentation Associated conditions Stokes–Adams attacks can be precipitated by this condition. These involve a temporary loss of consciousness resulting from marked slowing of the heart when the atrial impulse is no longer conducted to the ventricles. This should not be confused with the catastrophic loss of heartbeat seen with ventricular fibrillation or asystole. History It was described independently by Maurice Lev and Jean Lenègre in 1964, but the condition is generally called after Lev. See also * Heart block Heart block (HB) is a disorder in the heart's rhythm due to a fault in the natural pacemaker. This is caused by an obstruction – a block – in the elect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brugada Syndrome
Brugada syndrome (BrS) is a genetic disorder in which the electrical activity of the heart is abnormal due to channelopathy. It increases the risk of abnormal heart rhythms and sudden cardiac death. Those affected may have episodes of syncope. The abnormal heart rhythms seen in those with Brugada syndrome often occur at rest. They may be triggered by a fever. About a quarter of those with Brugada syndrome have a family member who also has the condition. Some cases may be due to a new genetic mutation or certain medications. The most commonly involved gene is SCN5A which encodes the cardiac sodium channel. Diagnosis is typically by electrocardiogram (ECG), however, the abnormalities may not be consistently present. Medications such as ajmaline may be used to reveal the ECG changes. Similar ECG patterns may be seen in certain electrolyte disturbances or when the blood supply to the heart has been reduced. There is no cure for Brugada syndrome. Those at higher risk of sudden ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PKP2
Plakophilin-2 is a protein that in humans is encoded by the ''PKP2'' gene. Plakophilin 2 is expressed in skin and cardiac muscle, where it functions to link cadherins to intermediate filaments in the cytoskeleton. In cardiac muscle, plakophilin-2 is found in desmosome structures located within intercalated discs. Mutations in ''PKP2'' have been shown to be causal in arrhythmogenic right ventricular cardiomyopathy. Structure Two splice variants of the ''PKP2'' gene have been identified. The first has a molecular weight of 97.4 kDa (881 amino acids) and the second of molecular weight of 92.7 kDa (837 amino acids). A processed pseudogene with high similarity to this locus has been mapped to chromosome 12p13. Plakophilin-2 is a member of the armadillo repeat and plakophilin protein family. Plakophilin proteins contain nine central, conserved armadillo repeat domains flanked by N-terminal and C-terminal domains. Alternately spliced transcripts encoding protein isoforms have been ident ... [...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] |
CAMK2D
Calcium/calmodulin-dependent protein kinase type II delta chain is an enzyme that in humans is encoded by the ''CAMK2D'' gene. The product of this gene belongs to the serine/threonine protein kinase family and to the Ca2+/calmodulin-dependent protein kinase subfamily. Calcium signaling is crucial for several aspects of plasticity at glutamatergic synapses. In mammalian cells, the enzyme is composed of four different chains: alpha, beta, gamma, and delta. The product of this gene is a delta chain. Four alternatively spliced transcript variants that encode three different isoforms A protein isoform, or "protein variant", is a member of a set of highly similar proteins that originate from a single gene or gene family and are the result of genetic differences. While many perform the same or similar biological roles, some iso ... have been characterized to date. Distinct isoforms of this chain have different expression patterns. References Further reading * * * * * * * * * * * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calmodulin
Calmodulin (CaM) (an abbreviation for calcium-modulated protein) is a multifunctional intermediate calcium-binding messenger protein expressed in all eukaryotic cells. It is an intracellular target of the secondary messenger Ca2+, and the binding of Ca2+ is required for the activation of calmodulin. Once bound to Ca2+, calmodulin acts as part of a calcium signal transduction pathway by modifying its interactions with various target proteins such as kinases or phosphatases. Structure Calmodulin is a small, highly conserved protein that is 148 amino acids long (16.7 kDa). The protein has two approximately symmetrical globular domains (the N- and C- domains) each containing a pair of EF hand motifs separated by a flexible linker region for a total of four Ca2+ binding sites, two in each globular domain. In the Ca2+-free state, the helices that form the four EF-hands are collapsed in a compact orientation, and the central linker is disordered; in the Ca2+-saturated state, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SCN4B
Sodium channel β-subunit 4, also known as SCN4B or Naβ4, is an auxiliary sodium channel subunit that can alter the kinetics of sodium channels. The protein is encoded by the ''SCN4B'' gene. Mutations in the ''SCN4B'' are associated with long QT syndrome. SCN4B might additionally function as a cell adhesion molecule. See also * Sodium channel Sodium channels are integral membrane proteins that form ion channels, conducting sodium ions (Na+) through a cell's membrane. They belong to the superfamily of cation channels and can be classified according to the trigger that opens the channel ... References * * * * * * * * External links * {{PDBe-KB2, Q8IWT1, Human Sodium channel subunit beta-4 (SCN4B) Sodium channels ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SCN3B
Sodium channel subunit beta-3 is a protein that in humans is encoded by the ''SCN3B'' gene. Two alternatively spliced variants, encoding the same protein, have been identified. Function Voltage-gated sodium channels are transmembrane glycoprotein complexes composed of a large alpha subunit and one or more regulatory beta subunits. They are responsible for the generation and propagation of action potentials in neurons and muscle. This gene encodes one member of the sodium channel beta subunit gene family, and influences the inactivation kinetics of the sodium channel. Clinical significance Mutations in the gene are associated with abnormal cardiac electrophysiology. See also * Sodium channel Sodium channels are integral membrane proteins that form ion channels, conducting sodium ions (Na+) through a cell's membrane. They belong to the superfamily of cation channels and can be classified according to the trigger that opens the channel ... References Further reading * * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SCN2B
Sodium channel subunit beta-2 is a protein that in humans is encoded by the ''SCN2B'' gene. See also * Sodium channel Sodium channels are integral membrane proteins that form ion channels, conducting sodium ions (Na+) through a cell's membrane. They belong to the superfamily of cation channels and can be classified according to the trigger that opens the chann ... References Further reading * * * * * * * * * * External links * * Ion channels {{membrane-protein-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SCN1B
Sodium channel subunit beta-1 is a protein that in humans is encoded by the ''SCN1B'' gene. Voltage-gated sodium channels are essential for the generation and propagation of action potentials in striated muscle and neuronal tissues. Biochemically, they consist of a large alpha subunit and 1 or 2 smaller beta subunits, such as SCN1B. The alpha subunit alone can exhibit all the functional attributes of a voltage-gated Na+ channel, but requires a beta-1 subunit for normal inactivation kinetics. upplied by OMIMref name="entrez" /> Clinical significance Mutation in the SCN1B gene are associated with disorders such as Brugada syndrome, Dravet Syndrome, and GEFS. See also * Sodium channel Sodium channels are integral membrane proteins that form ion channels, conducting sodium ions (Na+) through a cell's membrane. They belong to the superfamily of cation channels and can be classified according to the trigger that opens the channel ... References Further reading * * * * * * * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
