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MYL2
Myosin regulatory light chain 2, ventricular/cardiac muscle isoform (MLC-2) also known as the regulatory light chain of myosin (RLC) is a protein that in humans is encoded by the ''MYL2'' gene. This cardiac ventricular RLC isoform is distinct from that expressed in skeletal muscle ( MYLPF), smooth muscle ( MYL12B) and cardiac atrial muscle (MYL7). Ventricular myosin light chain-2 (MLC-2v) refers to the ventricular cardiac muscle form of myosin light chain 2 (Myl2). MLC-2v is a 19-KDa protein composed of 166 amino acids, that belongs to the EF-hand Ca2+ binding superfamily. MLC-2v interacts with the neck/tail region of the muscle thick filament protein myosin to regulate myosin motility and function. Structure Cardiac, ventricular RLC is an 18.8 kDa protein composed of 166 amino acids. RLC and the second ventricular light chain, essential light chain (ELC, MYL3), are non-covalently bound to IQXXXRGXXXR motifs in the 9 nm S1-S2 lever arm of the myosin head, both alpha (MYH6) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MYL7
Atrial Light Chain-2 (ALC-2) also known as Myosin regulatory light chain 2, atrial isoform (MLC2a) is a protein that in humans is encoded by the ''MYL7'' gene. ALC-2 expression is restricted to cardiac muscle atria in healthy individuals, where it functions to modulate cardiac development and contractility. In human diseases, including hypertrophic cardiomyopathy, dilated cardiomyopathy, ischemic cardiomyopathy and others, ALC-2 expression is altered. Structure Human ALC-2 protein has a molecular weight of 19.4 kDa and is composed of 175 amino acids. ALC-2 is an EF hand protein that binds to the neck region of alpha myosin heavy chain. ALC-2 and the ventricular isoform, VLC-2, share 59% homology, showing significant differences at their N-termini and at the regulatory phosphorylation site(s), Serine-15 and Serine/Asparagine-14. Function ALC-2 expression has proven to be a useful marker of cardiac muscle chamber distinction, development and differentiation. ALC-2 shows a p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MYL3
Myosin essential light chain (ELC), ventricular/cardiac isoform is a protein that in humans is encoded by the ''MYL3'' gene. This cardiac ventricular/slow skeletal ELC isoform is distinct from that expressed in fast skeletal muscle (MYL1) and cardiac atrial muscle (MYL4). Ventricular ELC is part of the myosin molecule and is important in modulating cardiac muscle contraction. Structure Cardiac, ventricular ELC is 21.9 kDa and composed of 195 amino acidsSee human MYL3 sequences features here. Cardiac ELC and the second light chain, regulatory light chain (RLC, MYL2), are non-covalently bound to IQXXXRGXXXR motifs in the 9 nm S1-S2 lever arm of the myosin head, both alpha (MYH6) and beta (MYH7) isoforms. Both light chains are members of the EF-hand superfamily of proteins, which possess helix-loop-helix motifs in two globular domains connected by an alpha-helical linker. Though EF hand motifs are specialized to bind divalent ions such as calcium, cardiac ELC does not bind calci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypertrophic Cardiomyopathy
Hypertrophic cardiomyopathy (HCM, or HOCM when obstructive) is a condition in which the heart becomes thickened without an obvious cause. The parts of the heart most commonly affected are the interventricular septum and the ventricles. This results in the heart being less able to pump blood effectively and also may cause electrical conduction problems. People who have HCM may have a range of symptoms. People may be asymptomatic, or may have fatigue, leg swelling, and shortness of breath. It may also result in chest pain or fainting. Symptoms may be worse when the person is dehydrated. Complications may include heart failure, an irregular heartbeat, and sudden cardiac death. HCM is most commonly inherited from a person's parents in an autosomal dominant pattern. It is often due to mutations in certain genes involved with making heart muscle proteins. Other inherited causes of left ventricular hypertrophy may include Fabry disease, Friedreich's ataxia, and certain medica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MYLK3
Myosin light chain kinase 3 also known as MYLK3, is an enzyme which in humans is encoded by the ''MYLK3'' gene. Function Phosphorylation of cardiac myosin heavy chains (see MYH7B) and light chains (see MYL2) by a kinase, such as MYLK3, potentiates the force and rate of cross-bridge recruitment in cardiac myocytes. See also * Myosin light-chain kinase Myosin light-chain kinase also known as MYLK or MLCK is a serine/threonine-specific protein kinase that phosphorylates a specific myosin light chain, namely, the regulatory light chain of myosin II. General structural features While there ar ... References Further reading * * * * * * * * * * EC 2.7.11 {{gene-16-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MYH7
MYH7 is a gene encoding a myosin heavy chain beta (MHC-β) isoform (slow twitch) expressed primarily in the heart, but also in skeletal muscles (type I fibers). This isoform is distinct from the fast isoform of cardiac myosin heavy chain, MYH6, referred to as MHC-α. MHC-β is the major protein comprising the thick filament in cardiac muscle and plays a major role in cardiac muscle contraction. Structure MHC-β is a 223 kDa protein composed of 1935 amino acids. MHC-β is a hexameric, asymmetric motor forming the bulk of the thick filament in cardiac muscle. MHC-β is composed of N-terminal globular heads (20 nm) that project laterally, and alpha helical tails (130 nm) that dimerize and multimerize into a coiled-coil motif to form the light meromyosin (LMM), thick filament rod. The 9 nm alpha-helical neck region of each MHC-β head non-covalently binds two light chains, essential light chain (MYL3) and regulatory light chain (MYL2). Approximately 300 myosin molecu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EF-hand
The EF hand is a helix–loop–helix structural domain or ''motif'' found in a large family of calcium-binding proteins. The EF-hand motif contains a helix–loop–helix topology, much like the spread thumb and forefinger of the human hand, in which the Ca2+ ions are coordinated by ligands within the loop. The motif takes its name from traditional nomenclature used in describing the protein parvalbumin, which contains three such motifs and is probably involved in muscle relaxation via its calcium-binding activity. The EF-hand consists of two alpha helices linked by a short loop region (usually about 12 amino acids) that usually binds calcium ions. EF-hands also appear in each structural domain of the signaling protein calmodulin and in the muscle protein troponin-C. Calcium ion binding site The calcium ion is coordinated in a pentagonal bipyramidal configuration. The six residues involved in the binding are in positions 1, 3, 5, 7, 9 and 12; these residues are denoted by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fractional Shortening
A ventricle is one of two large chambers toward the bottom of the heart that collect and expel blood towards the peripheral beds within the body and lungs. The blood pumped by a ventricle is supplied by an atrium, an adjacent chamber in the upper heart that is smaller than a ventricle. Interventricular means between the ventricles (for example the interventricular septum), while intraventricular means within one ventricle (for example an intraventricular block). In a four-chambered heart, such as that in humans, there are two ventricles that operate in a double circulatory system: the right ventricle pumps blood into the pulmonary circulation to the lungs, and the left ventricle pumps blood into the systemic circulation through the aorta. Structure Ventricles have thicker walls than atria and generate higher blood pressures. The physiological load on the ventricles requiring pumping of blood throughout the body and lungs is much greater than the pressure generated by the atria t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TNNI3
Troponin I, cardiac muscle is a protein that in humans is encoded by the ''TNNI3'' gene. It is a tissue-specific subtype of troponin I, which in turn is a part of the troponin complex image:Troponin Ribbon Diagram.png, 400px, Ribbon representation of the human cardiac troponin core complex (52 kDa core) in the calcium-saturated form. Blue = troponin C; green = troponin I; magenta = troponin T.; ; rendered with PyMOL Troponin, .... The ''TNNI3'' gene encoding cardiac troponin I (cTnI) is located at 19q13.4 in the human chromosomal genome. Human cTnI is a 24 kDa protein consisting of 210 amino acids with isoelectric point (pI) of 9.87. cTnI is exclusively expressed in adult cardiac muscle. Gene evolution left, Figure 1: A phylogenetic tree is derived from alignment of amino acid sequences. cTnI has diverged from the skeletal muscle isoforms of TnI (slow TnI and fast TnI) mainly with a unique N-terminal extension. The amino acid sequence of cTnI is strongly conserved among ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myofilament
Myofilaments are the three protein filaments of myofibrils in muscle cells. The main proteins involved are myosin, actin, and titin. Myosin and actin are the ''contractile proteins'' and titin is an elastic protein. The myofilaments act together in muscle contraction, and in order of size are a thick one of mostly myosin, a thin one of mostly actin, and a very thin one of mostly titin. Types of muscle tissue are striated skeletal muscle and cardiac muscle, obliquely striated muscle (found in some invertebrates), and non-striated smooth muscle. Various arrangements of myofilaments create different muscles. Striated muscle has transverse bands of filaments. In obliquely striated muscle, the filaments are staggered. Smooth muscle has irregular arrangements of filaments. Structure There are three different types of myofilaments: thick, thin, and elastic filaments. *Thick filaments consist primarily of a type of myosin, a motor protein – myosin II. Each thick filament is approx ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MYBPC3
The myosin-binding protein C, cardiac-type is a protein that in humans is encoded by the ''MYBPC3'' gene. This isoform is expressed exclusively in heart muscle during human and mouse development, and is distinct from those expressed in slow skeletal muscle (MYBPC1) and fast skeletal muscle (MYBPC2). Structure cMyBP-C is a 140.5 kDa protein composed of 1273 amino acids. cMyBP-C is a myosin-associated protein that binds at 43 nm intervals along the myosin thick filament backbone, stretching for 200 nm on either side of the M-line within the crossbridge-bearing zone (C-region) of the A band in striated muscle. The approximate stoichiometry of cMyBP-C along the thick filament is 1 per 9-10 myosin molecules, or 37 cMyBP-C molecules per thick filament. In addition to myosin, cMyBP-C also binds titin and actin. The cMyBP-C isoform expressed in cardiac muscle differs from those expressed in slow and fast skeletal muscle (MYBPC1 and MYBPC2, respectively) by three features: (1) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dobutamine
Dobutamine is a medication used in the treatment of cardiogenic shock (as a result of inadequate tissue perfusion) and severe heart failure. It may also be used in certain types of cardiac stress tests. It is given by IV only, as an injection into a vein or intraosseous as a continuous infusion. The amount of medication needs to be adjusted to the desired effect. Onset of effects is generally seen within 2 minutes. It has a half-life of two minutes. This drug is generally only administered short term, although it may be used for longer periods to relieve symptoms of heart failure in patients awaiting heart transplantation. Common side effects include a fast heart rate, an irregular heart beat, and inflammation at the site of injection. Use is not recommended in those with idiopathic hypertrophic subaortic stenosis. It primarily works by direct stimulation of β1 receptors, which increases the strength of the heart's contractions, leading to a positive ionotrophic effect. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inotropic
An inotrope is an agent that alters the force or energy of muscular contractions. Negatively inotropic agents weaken the force of muscular contractions. Positively inotropic agents increase the strength of muscular contraction. The term ''inotropic state'' is most commonly used in reference to various drugs that affect the strength of contraction of heart muscle. However, it can also refer to pathological conditions. For example, enlarged heart muscle can increase inotropic state, whereas dead heart muscle can decrease it. Medical uses Both positive and negative inotropes are used in the management of various cardiovascular conditions. The choice of agent depends largely on specific pharmacological effects of individual agents with respect to the condition. One of the most important factors affecting inotropic state is the level of calcium in the cytoplasm of the muscle cell. Positive inotropes usually increase this level, while negative inotropes decrease it. However, not al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
