query: the thin contractile protein of a muscle cell is known as

pos: Myofibril Myofibril A myofibril (also known as a muscle fibril) is a basic rod-like unit of a muscle cell. Muscles are composed of tubular cells called myocytes, known as muscle fibers in striated muscle, and these cells in turn contain many chains of myofibrils. They are created during embryonic development in a process known as myogenesis. Myofibrils are composed of long proteins including actin, myosin, and titin, and other proteins that hold them together. These proteins are organized into thick and thin filaments called myofilaments, which repeat along the length of the myofibril in sections called sarcomeres. Muscles contract by sliding

pos: Myocyte the cell can have negative prognostic impact. Each muscle fiber contains myofibrils, which are very long chains of sarcomeres, the contractile units of the cell. A cell from the biceps brachii muscle may contain 100,000 sarcomeres. The myofibrils of smooth muscle cells are not arranged into sarcomeres. The sarcomeres are composed of thin and thick filaments. Thin filaments are made of actin and attach at Z lines which help them line up correctly with each other. Troponins are found at intervals along the thin filaments. Thick filaments are made of the elongated protein myosin. The sarcomere does not contain organelles

pos: Myofilament cardiac muscle, the actin and myosin filaments each have a specific and constant length in the order of a few micrometers, far less than the length of the elongated muscle cell (a few millimeters in the case of human skeletal muscle cells). The filaments are organized into repeated subunits along the length of the myofibril. These subunits are called sarcomeres. The contractile nature of this protein complex is based on the structure of the thick and thin filaments. The thick filament, myosin, has a double-headed structure, with the heads positioned at opposite ends of the molecule. During muscle contraction, the

pos: ACTA2 multisystemic smooth muscle dysfunction syndrome. Alpha-smooth muscle actin (α-SMA) is commonly used as a marker of myofibroblast formation. ACTA2 Alpha-actin-2 also known as actin, aortic smooth muscle or alpha smooth muscle actin (α-SMA, SMactin, alpha-SM-actin, ASMA) is a protein that in humans is encoded by the "ACTA2" gene located on 10q22-q24. Actin alpha 2, the human aortic smooth muscle actin gene, is one of six different actin isoforms which have been identified. Actins are highly conserved proteins that are involved in cell motility, structure and integrity. Alpha actins are a major constituent of the contractile apparatus. Mutations in this gene

pos: Actin the motor-protein myosin (typically around 15 nm in diameter). These myofibrils use energy derived from ATP to create movements of cells, such as muscle contraction. Using the hydrolysis of ATP for energy, myosin heads undergo a cycle during which they attach to thin filaments, exert a tension, and then, depending on the load, perform a power stroke that causes the thin filaments to slide past, shortening the muscle. In contractile bundles, the actin-bundling protein alpha-actinin separates each thin filament by ~35 nm. This increase in distance allows thick filaments to fit in between and interact, enabling deformation or contraction. In

pos: Myofilament Myofilament Myofilaments are the filaments of myofibrils, constructed from proteins, principally myosin or actin. Types of muscle are striated muscle (such as skeletal muscle and cardiac muscle), obliquely striated muscle (found in some invertebrates), and 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. There are three different types of myofilaments: thick, thin, and elastic filaments. The protein complex composed of actin myosin, contractile proteins, is sometimes referred to as "actomyosin". In striated muscle, such as skeletal and

pos: Nebulin disorganization and degeneration occurred rapidly in these mice, indicating the nebulin is essential for maintaining the structural integrity of myofibrils. Witt and colleagues had similar results in their mice, which also died postnatally with reduced thin filament length and contractile function. These nebulin-knockout mice are being investigated as animal models of nemaline myopathy. Nebulin Nebulin is an actin-binding protein which is localized to the thin filament of the sarcomeres in skeletal muscle. It is a very large protein (600–900 kDa) and binds as many as 200 actin monomers. Because its length is proportional to thin filament length, it is believed

pos: ACTA2 ACTA2 Alpha-actin-2 also known as actin, aortic smooth muscle or alpha smooth muscle actin (α-SMA, SMactin, alpha-SM-actin, ASMA) is a protein that in humans is encoded by the "ACTA2" gene located on 10q22-q24. Actin alpha 2, the human aortic smooth muscle actin gene, is one of six different actin isoforms which have been identified. Actins are highly conserved proteins that are involved in cell motility, structure and integrity. Alpha actins are a major constituent of the contractile apparatus. Mutations in this gene cause a variety of vascular diseases, such as thoracic aortic disease, coronary artery disease, stroke, Moyamoya disease, and

pos: Sarcomere on the actin. Calcium ions bind with troponin-C molecules (which are dispersed throughout the tropomyosin protein) and alter the structure of the tropomyosin, forcing it to reveal the cross-bridge binding site on the actin. The concentration of calcium within muscle cells is controlled by the sarcoplasmic reticulum, a unique form of endoplasmic reticulum in the sarcoplasm. Muscle contraction ends when calcium ions are pumped back into the sarcoplasmic reticulum, allowing the contractile apparatus and, thus, muscle cell to relax. During stimulation of the muscle cell, the motor neuron releases the neurotransmitter acetylcholine, which travels across the neuromuscular junction (the synapse

pos: PDLIM3 PDLIM3 Actin-associated LIM protein (ALP), also known as PDZ and LIM domain protein 3 is a protein that in humans is encoded by the "PDLIM3" gene. ALP is highly expressed in cardiac and skeletal muscle, where it localizes to Z-discs and intercalated discs. ALP functions to enhance the crosslinking of actin by alpha actinin-2 and also appears to be essential for right ventricular chamber formation and contractile function. ALP exists primarily as two alternatively spliced variants; a 39.2 kDa (364 amino acids) protein in skeletal muscle and a 34.3 kDa (316 amino acids) protein in cardiac muscle and smooth muscle.

pos: Cardiac muscle the length of the slide over each other in what is known as the sliding filament hypothesis. There are two kinds of myofilaments, thick filaments composed of the protein myosin, and thin filaments composed of the proteins actin, troponin and tropomyosin. As the thick and thin filaments slide past each other the cell becomes shorter and fatter. In a mechanism known as crossbridge cycling, calcium ions bind to the protein troponin, which along with tropomyosin then uncover key binding sites on actin. Myosin, in the thick filament, can then bind to actin, pulling the thick filaments along the thin filaments.

pos: Dystrophin the fibrous endomysium of the entire muscle fiber. Dystrophin supports muscle fiber strength, and the absence of dystrophin reduces muscle stiffness, increases sarcolemmal deformability, and compromises the mechanical stability of costameres and their connections to nearby myofibrils. This has been shown in recent studies where biomechanical properties of the sarcolemma and its links through costameres to the contractile apparatus were measured, and helps to prevent muscle fiber injury. Movement of thin filaments (actin) creates a pulling force on the extracellular connective tissue that eventually becomes the tendon of the muscle. The dystrophin associated protein complex also helps scaffold various signalling

pos: Muscle hypertrophy their relationship to hypertrophy showed that damage was unrelated to hypertrophy. In fact, in that study the authors showed that it was not until the damage subsided that protein synthesis was directed to muscle growth. In the bodybuilding and fitness community and even in some academic books skeletal muscle hypertrophy is described as being in one of two types: Sarcoplasmic or myofibrillar. According to this hypothesis, during sarcoplasmic hypertrophy, the volume of sarcoplasmic fluid in the muscle cell increases with no accompanying increase in muscular strength, whereas during myofibrillar hypertrophy, actin and myosin contractile proteins increase in number and add

pos: Actin Actin Actin is a family of globular multi-functional proteins that form microfilaments. It is found in essentially all eukaryotic cells (the only known exception being nematode sperm), where it may be present at a concentration of over 100 μM; its mass is roughly 42-kDa, with a diameter of 4 to 7 nm. An actin protein is the monomeric subunit of two types of filaments in cells: microfilaments, one of the three major components of the cytoskeleton, and thin filaments, part of the contractile apparatus in muscle cells. It can be present as either a free monomer called G-actin (globular) or

pos: Stress fiber Stress fiber Stress fibers are contractile actin bundles found in non-muscle cells. They are composed of actin (microfilaments) and non-muscle myosin II (NMMII), and also contain various crosslinking proteins, such as α-actinin, to form a highly regulated actomyosin structure within non-muscle cells. Stress fibers have been shown to play an important role in cellular contractility, providing force for a number of functions such as cell adhesion, migration and morphogenesis. Stress fibers are primarily composed of actin and myosin. Actin is a ~43kDa globular protein, and can polymerize to form long filamentous structures.These filaments are made of two strands of actin

pos: Myoepithelial cell epithelium. Each cell consists of a cell body from which 4-8 processes radiate and embrace the secretory unit. Myoepithelial cells have contractile functions. They help in expelling secretions from the lumen of secretory units and facilitate the movement of saliva in salivary ducts. Myoepithelial cell Myoepithelial cells (sometimes referred to as myoepithelium) are cells usually found in glandular epithelium as a thin layer above the basement membrane but generally beneath the luminal cells. These may be positive for alpha smooth muscle actin and can contract and expel the secretions of exocrine glands. They are found in the sweat glands, mammary

pos: Muscle This author uses an example of the contractile elements present in the porifera or sponges that do truly lack this striated muscle containing this protein. Furthermore, Steinmetz et al. present evidence for a polyphyletic origin of striated muscle cell development through their analysis of morphological and molecular markers that are present in bilaterians and absent in cnidarians, ctenophores, and bilaterians. Steimetz et al. showed that the traditional morphological and regulatory markers such as actin, the ability to couple myosin side chains phosphorylation to higher concentrations of the positive concentrations of calcium, and other MyHC elements are present in all metazoans

pos: NRAP an adaptive response to correct for disorganized actin thin filament architecture at intercalated disc junctions in cardiomyocytes during dilated cardiomyopathy. NRAP Nebulin-related-anchoring protein (N-RAP) is a protein that in humans is encoded by the "NRAP" gene. N-RAP is a muscle-specific isoform belonging to the nebulin family of proteins. This family is composed of 5 members: N-RAP, nebulin, nebulette, LASP-1 and LASP-2. N-RAP is involved in both myofibrillar myogenesis during development and cell-cell connections in mature muscle. N-RAP is a 197 kDa protein composed of 1730 amino acids. As a member of the nebulin family of proteins, N-RAP is characterized by

pos: MYLK MYLK Myosin light chain kinase, smooth muscle also known as kinase-related protein (KRP) or telokin is an enzyme that in humans is encoded by the "MYLK" gene. This gene, a muscle member of the immunoglobulin gene superfamily, encodes myosin light chain kinase which is a calcium/calmodulin dependent enzyme. This kinase phosphorylates myosin regulatory light chains to facilitate myosin interaction with actin filaments to produce contractile activity. This gene encodes both smooth muscle and nonmuscle isoforms. In addition, using a separate promoter in an intron in the 3' region, it encodes telokin, a small protein identical in sequence to the C-terminus

pos: Myofibril the thick (myosin) and thin (actin) filaments along each other. The filaments of myofibrils, myofilaments, consist of two types, thick and thin: The protein complex composed of actin and myosin is sometimes referred to as "actinomyosin". In striated muscle, such as skeletal and cardiac muscle, the actin and myosin filaments each have a specific and constant length on the order of a few micrometers, far less than the length of the elongated muscle cell (a few millimeters in the case of human skeletal muscle cells). The filaments are organized into repeated subunits along the length of the myofibril. These subunits

pos: Nebulin Nebulin Nebulin is an actin-binding protein which is localized to the thin filament of the sarcomeres in skeletal muscle. It is a very large protein (600–900 kDa) and binds as many as 200 actin monomers. Because its length is proportional to thin filament length, it is believed that nebulin acts as a thin filament "ruler" and regulates thin filament length during sarcomere assembly. Other functions of nebulin, such as a role in cell signaling, remain uncertain. Nebulin has also been shown to regulate actin-myosin interactions by inhibiting ATPase activity in a calcium-calmodulin sensitive manner. Mutations in nebulin cause some cases

pos: Smooth muscle 1:3 range. A typical value for healthy young adults is 1:2.2.;; Smooth muscle does not contain the protein troponin; instead calmodulin (which takes on the regulatory role in smooth muscle), caldesmon and calponin are significant proteins expressed within smooth muscle. Also, all three of these proteins may have a role in inhibiting the ATPase activity of the myosin complex that otherwise provides energy to fuel muscle contraction. The myosin and actin are the contractile parts of continuous chains of tensile structures that stretch both across and between smooth muscle cells. The actin filaments of contractile units are attached to "dense

pos: Cytokinesis cell) at the cell cortex (adjacent to the cell membrane). Rho protein family (RhoA protein in mammalian cells) is a key regulator of contractile ring formation and contraction in animal cells. The RhoA pathway promotes assembly of the actin-myosin ring by two main effectors. First, RhoA stimulates nucleation of unbranched actin filaments by activation of Diaphanous-related formins. This local generation of new actin filaments is important for the contractile ring formation. This actin filament formation process also requires a protein called profilin, which binds to actin monomers and helps load them onto the filament end. Second, RhoA promotes myosin II

pos: Tropomyosin unit of skeletal muscle. The sarcomere is a highly structured protein array, consisting of interdigitating thick and thin filaments, where the thin filaments are tethered to a protein structure, the Z-line. The dynamic interaction between the thick and thin filaments results in muscle contraction. Myosin belongs to a family of motor proteins, and the muscle isoforms of this family comprise the thick filament. The thin filament is made of the skeletal muscle isoforms of actin. Each myosin protein 'paddles' along the thin actin filament, repeatedly binding to myosin-binding sites along the actin filament, ratcheting and letting go. In effect, the

pos: Cytokinesis mechanisms combined in the positioning of the cleavage furrow. The predominance of one particular signal varies between cell types and organisms. And the multitude and partial redundancy of signals may be required to make the system robust and to increase spatial precision. At the cytokinesis furrow, it is the actin-myosin contractile ring that drives the cleavage process, during which cell membrane and wall grow inward, which eventually pinches the mother cell in two. The key components of this ring are the filamentous protein actin and the motor protein myosin II. The contractile ring assembles equatorially (in the middle of the

pos: ACTG1 maintenance of the cytoskeleton. In vertebrates, three main groups of actin isoforms, alpha, beta and gamma have been identified. The alpha actins are found in muscle tissues and are a major constituent of the sarcomere contractile apparatus. The beta and gamma actins co-exist in most cell types as components of the cytoskeleton, and as mediators of internal cell motility. Actin, gamma 1, encoded by this gene, is found in non-muscle cells in the cytoplasm, and in muscle cells at costamere structures, or transverse points of cell-cell adhesion that run perpendicular to the long axis of myocytes. In myocytes, sarcomeres adhere

pos: Microfilament motility, one end of the actin filament elongates while the other end contracts, presumably by myosin II molecular motors. Additionally, they function as part of actomyosin-driven contractile molecular motors, wherein the thin filaments serve as tensile platforms for myosin's ATP-dependent pulling action in muscle contraction and pseudopod advancement. Microfilaments have a tough, flexible framework which helps the cell in movement. Actin and microfilament-mediated processes have long been a subject of research. American-German botanist George Engelmann (1879) suggested that many kinds of movement observed in plants and protozoa like cytoplasmic streaming and amoeboid movement were in fact a primitive version of

pos: Smooth muscle (mainly β-actin) that does not take part in contraction, but that polymerizes just below the plasma membrane in the presence of a contractile stimulant and may thereby assist in mechanical tension. Alpha actin is also expressed as distinct genetic isoforms such as smooth muscle, cardiac muscle and skeletal muscle specific isoforms of alpha actin. The ratio of actin to myosin is between 2:1 and 10:1 in smooth muscle. Conversely, from a mass ratio standpoint (as opposed to a molar ratio), myosin is the dominant protein in striated skeletal muscle with the actin to myosin ratio falling in the 1:2 to

pos: Catenin alpha-1 Catenin alpha-1 αE-catenin, also known as Catenin alpha-1 is a protein that in humans is encoded by the "CTNNA1" gene. αE-catenin is highly expressed in cardiac muscle and localizes to adherens junctions at intercalated disc structures where it functions to mediate the anchorage of actin filaments to the sarcolemma. αE-catenin also plays a role in tumor metastasis and skin cell function. Human αE-catenin protein is 100.0 kDa and 906 amino acids. Catenins (α,β,and γ (also known as plakoglobin)) were originally identified in complex with E-cadherin, an epithelial cell adhesion protein. αE-catenin is highly expressed in cardiac muscle and is homologous

pos: Peritubular myoid cell to the seminiferous tubule. ‘Myoid’ stems from the Greek ‘myo’ (/ˈmʌɪəʊ/), which means relating to muscle. (PTMs resemble smooth muscle cells under an electron microscope). Peritubular myoid cell A peritubular myoid (PTM) cell is one of the smooth muscle cells which surround the seminiferous tubules in the testis. These cells are present in all mammals but their organisation and abundance varies between species. The exact role of PTM cells is still somewhat uncertain and further work into this is needed. However, a number of functions of these cells have been established. They are contractile cells which contain actin filaments and

pos: Actinin alpha 3 Actinin alpha 3 Alpha-actinin-3, also known as alpha-actinin skeletal muscle isoform 3 or F-actin cross-linking protein, is a protein that in humans is encoded by the "ACTN3" gene. Alpha-actinin is an actin-binding protein with multiple roles in different cell types. This gene expression is limited to skeletal muscle. It is localized to the Z-disc and analogous dense bodies, where it helps to anchor the myofibrillar actin filaments. Skeletal muscle is composed of long cylindrical cells called muscle fibers. There are two types of muscle fibers, slow twitch or muscle contraction (type I) and fast twitch (type II). Slow twitch fibers

pos: Pancreatic stellate cell acidic protein. The expression of a diverse range of intermediate filament proteins enables the PaSC to harbour contractile abilities. Cellular extensions also enable the cells to sense their environment. Following inflammation or injury to the pancreas, quiescent PaSCs are activated to myofibroblast like cells, which expresses α- smooth muscle actin. Several morphological changes take place including nuclear enlargement and increased growth of the endoplasmic reticulum network. The activated PaSCs then grow in number, migrate and secrete extracellular matrix components such as type I collagen, chemokines and cytokines. Quiescent PaSCs produce metalloproteinases such as MMP-2, MMP-9, and MMP-13 and their inhibitors,

pos: TPM1 of head-to-tail overlap of subsequent Tm molecules to actin. Mutations in TPM1 have been associated with hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy. HCM mutations tend to cluster around the N-terminal region and a primary actin binding region known as period 5. TPM1 Tropomyosin alpha-1 chain is a protein that in humans is encoded by the "TPM1" gene. This gene is a member of the tropomyosin (Tm) family of highly conserved, widely distributed actin-binding proteins involved in the contractile system of striated and smooth muscles and the cytoskeleton of non-muscle cells. Tm is a 32.7 kDa protein composed of 284 amino

pos: Eccentric training role of eccentric training is to use these principles of energy conversion to strengthen muscle and tendon groups. The muscle has "tension producing tissue comprising small contractile units referred to as sarcomeres" that each contain a "thick (myosin) and thin (actin) myofilament (muscle filaments or proteins) that overlaps to format a cross-bridge bond (attachment)". When in a concentric exercise, shortening of a muscle occurs as the myosin and actin cross bridges repeatedly attach and detach to draw the actin across the myosin — creating force. Each cross-bridge attachment and detachment cycle is powered by the splitting of one molecule of

pos: TPM1 TPM1 Tropomyosin alpha-1 chain is a protein that in humans is encoded by the "TPM1" gene. This gene is a member of the tropomyosin (Tm) family of highly conserved, widely distributed actin-binding proteins involved in the contractile system of striated and smooth muscles and the cytoskeleton of non-muscle cells. Tm is a 32.7 kDa protein composed of 284 amino acids. Tm is a flexible protein homodimer or heterodimer composed of two alpha-helical chains, which adopt a bent coiled coil conformation to wrap around the seven actin molecules in a functional unit of muscle. It is polymerized end to end along

pos: Smooth muscle called focal adhesions) in the cell membrane of the smooth muscle cell, called the sarcolemma. The adherens junctions consist of large number of proteins including α-actinin, vinculin and cytoskeletal actin. The adherens junctions are scattered around "dense bands" that are circumfering the smooth muscle cell in a rib-like pattern. The dense band (or dense plaques) areas alternate with regions of membrane containing numerous caveolae. When complexes of actin and myosin contract, force is transduced to the sarcolemma through intermediate filaments attaching to such dense bands. During contraction, there is a spatial reorganization of the contractile machinery to optimize force development.

pos: Prokaryotic cytoskeleton ring structure located in the middle of the cell called the Z-ring that constricts during cell division, similar to the actin-myosin contractile ring in eukaryotes. The Z-ring is a highly dynamic structure that consists of numerous bundles of protofilaments that extend and shrink, although the mechanism behind Z-ring contraction and the number of protofilaments involved are unclear. FtsZ acts as an organizer protein and is required for cell division. It is the first component of the septum during cytokinesis, and it recruits all other known cell division proteins to the division site. Despite this functional similarity to actin, FtsZ is

pos: FtsZ produce a new cell wall between the dividing cells. FtsZ's role in cell division is analogous to that of actin in eukaryotic cell division, but, unlike the actin-myosin ring in eukaryotes, FtsZ has no known motor protein associated with it. The origin of the cytokinetic force, thus, remains unclear, but it is believed that the localized synthesis of new cell wall produces at least part of this force. In liposomes Osawa (2009) showed FtsZ is capable of exerting a contractile force with no other proteins present. Erickson (2009) proposed how the roles of tubulin-like proteins and actin-like proteins in cell

pos: CapZ CapZ In molecular biology CapZ, also known as CAPZ; CAZ1 and CAPPA1, is a protein composed of alpha and beta subunits. Its main function is to cap the barbed (plus) end of actin filaments in muscle cells. It is located in the Z band of the muscle sarcomere. This protein helps to stabilize the actin filaments protecting it from assembly and disassembly. The activity regulation of this protein can be done by other regulatory proteins that bind to the actin filaments blocking the CapZ, hence allowing assembly. CapZ is also known to play a role in cell signaling, as it

pos: Actinin alpha 3 injury risk. It appears that the XX genotype is associated with higher levels of muscle damage and a longer time required for recovery. ACTN3 has been shown to interact with Actinin, alpha 2. Actinin alpha 3 Alpha-actinin-3, also known as alpha-actinin skeletal muscle isoform 3 or F-actin cross-linking protein, is a protein that in humans is encoded by the "ACTN3" gene. Alpha-actinin is an actin-binding protein with multiple roles in different cell types. This gene expression is limited to skeletal muscle. It is localized to the Z-disc and analogous dense bodies, where it helps to anchor the myofibrillar actin filaments.

pos: Smooth muscle heavy and light chains allow for up to hundreds of different types of myosin structures, but it is unlikely that more than a few such combinations are actually used or permitted within a specific smooth muscle bed. In the uterus, a shift in myosin expression has been hypothesized to avail for changes in the directions of uterine contractions that are seen during the menstrual cycle. The thin filaments that form part of the contractile machinery are predominantly composed of α- and γ-actin. Smooth muscle α-actin (alpha actin) is the predominant isoform within smooth muscle. There are also lots of actin

pos: Troponin C type 1 Troponin C type 1 Troponin C, also known as TN-C or TnC, is a protein that resides in the troponin complex on actin thin filaments of striated muscle (cardiac, fast-twitch skeletal, or slow-twitch skeletal) and is responsible for binding calcium to activate muscle contraction. Troponin C is encoded by the "TNNC1" gene in humans for both cardiac and slow skeletal muscle. Cardiac troponin C (cTnC) is a 161-amino acid protein organized into two domains: the regulatory N-terminal domain (cNTnC, residues 1-86), the structural C-terminal domain (cCTnC, residues 93-161), and a flexible linker connecting the two domains (residues 87-92). Each domain

pos: Pericyte of capillaries and help to serve this function. Microvascular pericytes may not be contractile cells because they lack alpha-actin isoforms; structures that are common amongst other contractile cells. These cells communicate with endothelial cells via gap junctions and in turn cause endothelial cells to proliferate or be selectively inhibited. If this process did not occur, hyperplasia and abnormal vascular morphogenesis could occur. These types of pericyte can also phagocytose exogenous proteins. This suggests that the cell type might have been derived from microglia. A lineage relationship to other cell types has been proposed, including smooth muscle cells, neural cells, NG2

pos: Troponin C type 1 involving the thin filament, including actin-myosin cross-bridging and length dependent activation (also known as stretch activation or the Frank Starling law of the heart). All of these processes can be impacted by mutations (see section below on disease-causing mutations). Hypertrophic cardiomyopathy (HCM) is a common condition (prevalence >1:500) characterized by abnormal thickening of the ventricular muscle, classically in the intraventricular septal wall. HCM is described as a disease of the sarcomere, because mutations in the contractile proteins of the sarcomere have been identified in about half of patients with HCM. The cTnC mutations that have been associated with HCM are

pos: Smooth muscle part of this reorganization consists of vimentin being phosphorylated at Ser by a p21 activated kinase, resulting in some disassembly of vimentin polymers. Also, the number of myosin filaments is dynamic between the relaxed and contracted state in some tissues as the ratio of actin to myosin changes, and the length and number of myosin filaments change. Smooth muscle cells have been observed contracting in a spiral corkscrew fashion, and contractile proteins have been observed organizing into zones of actin and myosin along the axis of the cell. Smooth muscle-containing tissue needs to be stretched often, so elasticity is an

pos: Myofibril Myofibril A myofibril (also known as a muscle fibril) is a basic rod-like unit of a muscle cell. Muscles are composed of tubular cells called myocytes, known as muscle fibers in striated muscle, and these cells in turn contain many chains of myofibrils. They are created during embryonic development in a process known as myogenesis. Myofibrils are composed of long proteins including actin, myosin, and titin, and other proteins that hold them together. These proteins are organized into thick and thin filaments called myofilaments, which repeat along the length of the myofibril in sections called sarcomeres. Muscles contract by sliding

neg: MYH9 MYH9 Myosin-9 also known as myosin, heavy chain 9, non-muscle or non-muscle myosin heavy chain IIa (NMMHC-IIA) is a protein which in humans is encoded by the "MYH9" gene. Non-muscle myosin IIA (NM IIA) is expressed in most cells and tissues where it participates in a variety of processes requiring contractile force, such as cytokinesis, cell migration, polarization and adhesion, maintenance of cell shape, and signal transduction. Myosin IIs are motor proteins that are part of a superfamily composed of more than 30 classes. Class II myosins include muscle and non-muscle myosins that are organized as hexameric molecules consisting of

neg: ANK1 affinities for various target proteins are expressed in a tissue-specific, developmentally regulated manner. Most ankyrins are typically composed of three structural domains: an amino-terminal domain containing multiple ankyrin repeats; a central region with a highly conserved spectrin-binding domain; and a carboxy-terminal regulatory domain, which is the least conserved and subject to variation. The small ANK1 (sAnk1) protein splice variants makes contacts with obscurin, a giant protein surrounding the contractile apparatus in striated muscle. ANK1 has been shown to interact with T-cell lymphoma invasion and metastasis-inducing protein 1, Titin, RHAG and OBSCN. ANK1 Ankyrin 1, erythrocytic, also known as ANK1, is

neg: MYH11 MYH11 Myosin-11 is a protein that in humans is encoded by the "MYH11" gene. Myosin-11 is a smooth muscle myosin belonging to the myosin heavy chain family. Myosin-11 is a subunit of a hexameric protein that consists of two heavy chain subunits and two pairs of non-identical light chain subunits. It is a major contractile protein, converting chemical energy into mechanical energy through the hydrolysis of ATP. Alternative splicing generates isoforms that are differentially expressed, with ratios changing during muscle cell maturation. Thoracic aortic aneurysms leading to acute aortic dissections (TAAD) can be inherited in isolation or in association with

neg: Cardiac excitation-contraction coupling In the SAN cAMP binds to an ion channel involved in action potential initiation, speeding up the production of the action potential (see sinoatrial node for more detail). cAMP also, activates a protein called protein kinase A (PKA). PKA affects both the DHPR and RyR, increasing the rise in Ca within the contractile cells and therefore increasing rate of muscle contraction. PKA also affects the myofilaments as well as a protein called phospholamban (PLB; see sarcoplasmic reticulum for more details), speeding up the rate of Cadecline in the cell and so speeding up muscle relaxation. Parasympathetic nerves work by releasing

neg: Cardiac muscle such as may occur during abnormal heart rhythms such as ventricular fibrillation. Viewed through a microscope, cardiac muscle cells are roughly rectangular, measuring 100–150μm by 30–40μm. Individual cardiac muscle cells are joined together at their ends by intercalated disks to form long fibres. Each cell contains myofibrils, specialised protein fibres that slide past each other. These are organised into sarcomeres, the fundamental contractile units of muscle cells. The regular organisation of myofibrils into sarcomeres gives cardiac muscle cells a striped or striated appearance when looked at through a microscope, similar to skeletal muscle. These striations are caused by lighter I

neg: Cardiac muscle cell by disruptions to cardiac muscle cell growth and / or organization. Presentation can range from asymptomatic to sudden cardiac death. Cardiomyopathy can be caused by genetic, endocrine, environmental, or other factors. Cardiac muscle cell Cardiac muscle cells or cardiomyocytes (also known as myocardiocytes or cardiac myocytes) are the muscle cells (myocytes) that make up the cardiac muscle (heart muscle). Each myocardial cell contains myofibrils, which are specialized organelles consisting of long chains of sarcomeres, the fundamental contractile units of muscle cells. Cardiomyocytes show striations similar to those on skeletal muscle cells. Unlike multinucleated skeletal cells, the majority of cardiomyocytes contain

neg: Cardiac muscle cell Cardiac muscle cell Cardiac muscle cells or cardiomyocytes (also known as myocardiocytes or cardiac myocytes) are the muscle cells (myocytes) that make up the cardiac muscle (heart muscle). Each myocardial cell contains myofibrils, which are specialized organelles consisting of long chains of sarcomeres, the fundamental contractile units of muscle cells. Cardiomyocytes show striations similar to those on skeletal muscle cells. Unlike multinucleated skeletal cells, the majority of cardiomyocytes contain only one nucleus, although they may have as many as four. Cardiomyocytes have a high mitochondrial density, which allows them to produce adenosine triphosphate (ATP) quickly, making them highly resistant to

neg: Sarcoplasm inside the cell membrane (sarcolemma), and a smooth endoplasmic reticulum (specialized for muscle function and called the sarcoplasmic reticulum). While "sarcoplasm" and "myoplasm," viewed etymologically, might seem to be synonyms, they are not. Whereas sarcoplasm is a type of cytoplasm, myoplasm is the entire contractile portion of muscle tissue. Sarcoplasm Sarcoplasm is the cytoplasm of a myocyte (muscle fiber). It is comparable to the cytoplasm of other cells, but it contains unusually large amounts of "glycosomes" (granules of stored glycogen) and significant amounts of myoglobin, an oxygen-binding protein. The calcium ion concentration in sarcoplasma is also a special element of

neg: Germ-band extension from the asymmetric localization of proteins within individual cells. Immunofluorescence reveals that non-muscle Myosin II localizes to the anterior-posterior boundaries of cells, destabilizing adherens junctions, whereas the Bazooka/Par-3 complex localizes to dorsal-ventral boundaries, stabilizing adherens junctions. Moreover, "bazooka" mutants are defective in germ-band extension, which supports the idea that polarized protein localization is critical for cell rearrangements. One mechanism by which Myosin II might promote polarized cell remodeling is through contractile activity that creates tension orienting junctional disassembly. However, the precise mechanism in which asymmetrically localized protein complexes encourage directed intercalation remains disputed. The source that establishes planar polarity during

neg: Synemin it has been observed in a variety of cell types, it has been best studied in the sarcomere of skeletal myocytes. It localizes at the Z-disk and has been shown to bind to α-dystrobrevin, α-actinin, and desmin to act as a mechanical linker in transmitting force laterally throughout the tissue, especially between the contractile myofibrils and extracellular matrix. Synemin contributes to linkage between costameres and the contractile apparatus in skeletal muscle of synemin null animals. Synemin has properties very similar to the intermediate filament syncoilin. In particular, it binds to α-dystrobrevin in the dystrophin-associated protein complex to act as a

neg: Muscle that the MyHc genes are present in the sponges that have contractile elements but no true muscle cells. Furthermore, Steinmetz et all showed that the localization of this duplicated set of genes that serve both the function of facilitating the formation of striated muscle genes and cell regulation and movement genes were already separated into striated myhc and non-muscle myhc. This separation of the duplicated set of genes is shown through the localization of the striated myhc to the contractile vacuole in sponges while the non-muscle myhc was more diffusely expressed during developmental cell shape and change. Steinmetz et al.

neg: MYH1 is a major contractile protein that converts chemical energy into mechanical energy through the hydrolysis of ATP. Class II Myosins are hexameric proteins composed of a pair of myosin heavy chains (MYH) and two pairs of nonidentical light chains. Myosin heavy chains are encoded by a multigene family. In mammals, at least ten different myosin heavy chain (MYH) isoforms have been described from striated, smooth, but rarely in non-muscle cells. These isoforms show expression that is spatially and temporally regulated during development. MYH1 Myosin-1, also known as 'striated muscle myosin heavy chain 1', is a protein that in humans is

neg: Nebulin of the autosomal recessive disorder nemaline myopathy. A smaller member of the nebulin protein family, termed nebulette, is expressed in cardiac muscle. The structure of the SH3 domain of nebulin was determined by NMR. The SH3 domain from nebulin is composed of 60 amino acid residues, of which 30 percent is in the beta sheet secondary structure (7 strands; 18 residues). As of 2007, two knockout mouse models for nebulin have been developed to better understand its "in vivo" function. Bang and colleagues demonstrated that nebulin-knockout mice die postnatally, have reduced thin filament length, and impaired contractile function. Postnatal sarcomere

neg: Prostaglandin EP1 receptor also contract muscle cells, EP has been classified as a contractile type of prostanoid receptor. The activation of protein kinases C feeds back to phosphorylate and thereby desensitizes the activated EP receptor (see homologous desensitization but may also desensitize other types of prostanoid and non-prostanoid receptors (see heterologous desensitization). These desensitizations limit further EP receptor activation within the cell. Concurrently with the mobilization of these pathways, ligand-activated EP stimulates ERK, p38 mitogen-activated protein kinases, and CREB pathways that lead to cellular functional responses. Studies using animals genetically engineered to lack EP and supplemented by studies using treatment with EP receptor

neg: Sarcoplasmic reticulum (contractile units of the cell). Cardiac and skeletal muscle cells contain structures called transverse tubules (T-tubules), which are extensions of the cell membrane that travel into the centre of the cell. T-tubules are closely associated with a specific region of the SR, known as the terminal cisternae in skeletal muscle, with a distance of roughly 12 nanometers, separating them. This is the primary site of calcium release. The longitudinal SR are thinner projects, that run between the terminal cisternae/junctional SR, and are the location where ion channels necessary for calcium ion absorption are most abundant. These processes are explained in

neg: Muscle contraction can be dysregulated in many diseases.Though excitation–contraction coupling has been known for over half a century, it is still an active area of biomedical research. The general scheme is that an action potential arrives to depolarize the cell membrane. By mechanisms specific to the muscle type, this depolarization results in an increase in cytosolic calcium that is called a calcium transient. This increase in calcium activates calcium-sensitive contractile proteins that then use ATP to cause cell shortening. The mechanism for muscle contraction evaded scientists for years and requires continued research and updating. The sliding filament theory was independently developed by

neg: Muscle hypertrophy gynecomastia. A positive energy balance, when more calories are consumed rather than burned, is required for anabolism and therefore muscle hypertrophy. An increased requirement for protein, especially branch chained amino acids, is required for elevated protein synthesis that is seen in athletes training for muscle hypertrophy. Training variables, in the context of strength training, such as frequency, intensity, and total volume also directly affect the increase of muscle hypertrophy. A gradual increase in all of these training variables will yield the muscular hypertrophy. The message filters down to alter the pattern of gene expression. The additional contractile proteins appear to

neg: Reduced muscle mass, strength and performance in space weight) along with a concomitant loss in total protein and myofibrillar (the fraction that is composed of the contractile machinery of structural proteins) protein content of the targeted muscles. In some experiments, it has been reported that the myofibrillar fraction can be degraded to a greater extent than other muscle fractions. The general pattern demonstrates that a rapid loss in muscle weight and net total and myofibrillar protein content (concentration (mg/g X muscle weight) occurs during the first 7–10 days of unloading and this is followed by a more gradual loss in these constituents. The net result is that between

neg: Peritubular myoid cell and form several thin elongated layers, approximately 5-7 cell layers, and surround Sertoli cells. These are detected in the lamina propria of the seminiferous tubule and immunohistochemical studies have shown functional distinctions between these layers. The inner layers have been shown to express desmin, a smooth muscle phenotype, whereas the outer layers express vimentin, a connective tissue phenotype. In rodents, PTM cells are one layer thick. Both human and rodent PTM cells are joined by junctional complexes. Peritubular myoid cells are responsible for the contractile nature of the seminiferous tubule. This contraction helps move the spermatozoa and fluid to the

neg: Neuregulin 1 Therefore, growth of adult cardiac cells is commonly characterized by hypertrophy and an increased content of contractile proteins. However, studies have shown NRG-1 promotes myocardial regeneration through hyperplasia, and prevents hypertrophy surrounding infarcted areas. The cMLCK protein is an important regulator of sarcomere assembly through activation of the myosin regulatory light chain, as well as playing a role in heart contractility. In contrast to smooth and skeletal muscle MLCKs, cMLCK expression is restricted to cardiac myocytes. Overexpression of cMLCK increases cell contractility. Treatment of cardiac myocytes with rhNRG-1 significantly upregulated cMLCK expression or activity??? in CHF rat models, together with

neg: Telokin smooth muscle cell, whereas in large pulmonary arteries smooth muscle cell there is no change in either telokin or myosin light chain phosphorylation. When large pulmonary arteries smooth muscle cell were exposed to phenylephrine, myosin light chain phosphorylation increased with no change in telokin phosphorylation. In small pulmonary arteries, phosphorylated telokin may help maintain relaxation under unstimulated conditions, whereas in large pulmonary arteries, telokin's function remains undetermined. Telokin Telokin (also known as kinase-related protein or KRP) is an abundant protein found in smooth-muscle. It is identical to the C-terminus of myosin light-chain kinase. Telokin may play a role in the

neg: Intraglomerular mesangial cell Intraglomerular mesangial cell Intraglomerular mesangial cells are specialized pericytes located among the glomerular capillaries within a renal corpuscle of a kidney. Mesangial cells are of monocyte or smooth muscle origin, typically covering 30% of glomerular capillaries. They are both vimentin and desmin positive. There are five known functions of intraglomerular mesangial cells: structural support of glomerular capillaries, regulation of the glomerular filtration rate, mesangial matrix formation, phagocytosis, and monitoring of capillary lumen glucose concentration. Intraglomerular mesangial cells have contractile activity. The initiation of contraction of mesangial cells is similar to that of smooth muscle. Contraction of mesangial cells is coupled

neg: Smooth muscle force. Similar to the mechanism of vertebrate smooth muscle, there is a low calcium and low energy utilization catch phase. This sustained phase or catch phase has been attributed to a catch protein that has similarities to myosin light-chain kinase and the elastic protein-titin called twitchin. Clams and other bivalve mollusks use this catch phase of smooth muscle to keep their shell closed for prolonged periods with little energy usage. Although the structure and function is basically the same in smooth muscle cells in different organs, their specific effects or end-functions differ. The contractile function of vascular smooth muscle regulates

neg: Reflex bradycardia vagus nerve, the parasympathetic nervous system stimulates neurons that release the neurotransmitter acetylcholine (ACh) at synapses with cardiac muscle cells. Acetylcholine then binds to M muscarinic receptors, causing the decrease in heart rate that is referred to as reflex bradycardia. The M muscarinic receptors decrease the heart rate by inhibiting depolarization of the sinoatrial node via G protein-coupled receptors and through modulation of muscarinic potassium channels. Additionally, M receptors reduce the contractile forces of the atrial cardiac muscle and reduce the conduction velocity of the atrioventricular node (AV node). However, M receptors have no effect on the contractile forces of

neg: Intraglomerular mesangial cell the capillary lumen. Intraglomerular mesangial cell Intraglomerular mesangial cells are specialized pericytes located among the glomerular capillaries within a renal corpuscle of a kidney. Mesangial cells are of monocyte or smooth muscle origin, typically covering 30% of glomerular capillaries. They are both vimentin and desmin positive. There are five known functions of intraglomerular mesangial cells: structural support of glomerular capillaries, regulation of the glomerular filtration rate, mesangial matrix formation, phagocytosis, and monitoring of capillary lumen glucose concentration. Intraglomerular mesangial cells have contractile activity. The initiation of contraction of mesangial cells is similar to that of smooth muscle. Contraction of mesangial

neg: Contractile vacuole Contractile vacuole A contractile vacuole (CV) is a sub-cellular structure (organelle) involved in osmoregulation. It is found predominantly in protists and in unicellular algae. It was previously known as pulsatile or pulsating vacuole The contractile vacuole is a specialized type of vacuole that regulates the quantity of water inside a cell. In freshwater environments, the concentration of solutes is hypotonic, higher inside than outside the cell. Under these conditions, water osmosis causes water to accumulate in the cell from the external environment. The contractile vacuole acts as part of a protective mechanism that prevents the cell from absorbing too much

neg: Calcium sparks the cell. During evoked Ca sparks, all clusters of ryanodine receptors, throughout the cell are activated at almost exactly the same time. This produces an increase in Ca concentration across the whole cell (not just locally) and is known as a whole cell Ca transient. This Ca then binds to a protein, called troponin, initiating contraction, through a group of proteins known as myofilaments. In smooth muscle cells, the Ca released during a spark is used for muscle relaxation. This is because, the Ca that enters the cell via the DHPR in response to the action potential, stimulates both muscle

neg: Dystrophin Dystrophin Dystrophin is a rod-shaped cytoplasmic protein, and a vital part of a protein complex that connects the cytoskeleton of a muscle fiber to the surrounding extracellular matrix through the cell membrane. This complex is variously known as the costamere or the dystrophin-associated protein complex (DAPC). Many muscle proteins, such as α-dystrobrevin, syncoilin, synemin, sarcoglycan, dystroglycan, and sarcospan, colocalize with dystrophin at the costamere. The DMD gene, encoding the dystrophin protein, is one of the longest human genes known, covering 2.3 megabases (0.08% of the human genome) at locus Xp21. The primary transcript in muscle measures about 2,100 kilobases and

neg: Peritubular myoid cell contractile. He called them ‘’peritubular contractile cells’’. In 1969, Don Wayne Fawcett et al. termed these cells ‘’peritubular myoid cells’’, because of their similarities to smooth muscle cells. As PTMs became better characterized, the associated nomenclature underwent a series of changes. In very early literature these cells may be referred to as ‘modified connective tissue cells’ or ‘interlamellar cells’. Subsequent experiments resulted in renaming these cells to better reflect their contractile nature. The term ‘peritubular contractile cells’ was first used in 1967. In 1969, Don Fawcett labelled these cells as ‘peritubular myoid cells’. ‘Peritubular’ refers to their anatomical location: adjacent

neg: CAPZA2 be modulated by the calcium-binding protein S100A in skeletal and cardiac muscle tissues, as crosslinking studies have shown S100A to directly interaction with the C-terminal region of CapZ-alpha in the presence of calcium. CapZ appears to regulate intracellular signaling of contractile proteins in cardiac muscle. It has been demonstrated that the presence of CapZ at Z-discs modulates the ability of protein phosphatase 1 (PP1) to dephosphorylate cardiac myofilament proteins, including myosin binding protein C, troponin T and myosin regulatory light chain; likely because extraction of CapZ decreased the amount of myofilament-associated PP1. In humans undergoing exercise-induced muscle damage via 300

neg: LPAR1 LPAR1 Lysophosphatidic acid receptor 1 also known as LPA is a protein that in humans is encoded by the "LPAR1" gene. LPA is a G protein-coupled receptor that binds the lipid signaling molecule lysophosphatidic acid (LPA). The integral membrane protein encoded by this gene is a lysophosphatidic acid (LPA) receptor from a group known as EDG receptors. These receptors are members of the G protein-coupled receptor superfamily. Utilized by LPA for cell signaling, EDG receptors mediate diverse biologic functions, including proliferation, platelet aggregation, smooth muscle contraction, inhibition of neuroblastoma cell differentiation, chemotaxis, and tumor cell invasion. Alternative splicing of this

neg: MYH11 core-binding factor beta in a fusion with the C-terminal portion of the smooth muscle myosin heavy chain. This chromosomal rearrangement is associated with acute myeloid leukemia of the M4Eo subtype. MYH11 mutations appear to contribute to human intestinal cancer. MYH11 Myosin-11 is a protein that in humans is encoded by the "MYH11" gene. Myosin-11 is a smooth muscle myosin belonging to the myosin heavy chain family. Myosin-11 is a subunit of a hexameric protein that consists of two heavy chain subunits and two pairs of non-identical light chain subunits. It is a major contractile protein, converting chemical energy into mechanical

neg: ROCK1 (ALS), and pulmonary hypertension. ROCK1 ROCK1 is a protein serine/threonine kinase also known as rho-associated, coiled-coil-containing protein kinase 1. Other common names are ROKβ and P160ROCK. ROCK1 is a major downstream effecter of the small GTPase RhoA and is a regulator of the actomyosin cytoskeleton which promotes contractile force generation. ROCK1 plays a role in cancer and in particular cell motility, metastasis, and angiogenesis. ROCK1 is also the name of the gene that encodes the protein ROCK1, a serine/threonine kinase. ROCK1 is activated when bound to the GTP-bound form of RhoA. The human ROCK1 gene is located on human chromosome

neg: ROCK1 ROCK1 ROCK1 is a protein serine/threonine kinase also known as rho-associated, coiled-coil-containing protein kinase 1. Other common names are ROKβ and P160ROCK. ROCK1 is a major downstream effecter of the small GTPase RhoA and is a regulator of the actomyosin cytoskeleton which promotes contractile force generation. ROCK1 plays a role in cancer and in particular cell motility, metastasis, and angiogenesis. ROCK1 is also the name of the gene that encodes the protein ROCK1, a serine/threonine kinase. ROCK1 is activated when bound to the GTP-bound form of RhoA. The human ROCK1 gene is located on human chromosome 18 with specific location

neg: Inflammation to the overload principle to enhance their muscles, show moderate Z-disk streaming and major disruption of thick and thin filaments in parallel groups of sarcomeres as a result of the force of eccentric actions or stretching of tightened muscle fibers. This disruption of muscle fibers triggers white blood cells to increase following induced muscle soreness, leading to the inflammatory response observation from induced muscle soreness. Elevations in plasma enzymes, myoglobinemia, and abnormal muscle histology and ultrastructure are concluded to be associated with inflammatory response. High tension in the contractile-elastic system of muscle results in structural damage to the muscle fiber

neg: Myocyte structure forms the cross bridge that connects with the thin filaments. A myoblast is a type of embryonic progenitor cell that differentiates to give rise to muscle cells. Differentiation is regulated by myogenic regulatory factors, including MyoD, Myf5, myogenin, and MRF4. GATA4 and GATA6 also play a role in myocyte differentiation. Skeletal muscle fibers are made when myoblasts fuse together; muscle fibers therefore are cells with multiple nuclei, known as myonuclei, with each cell nucleus originating from a single myoblast. The fusion of myoblasts is specific to skeletal muscle (e.g., "biceps brachii") and not cardiac muscle or smooth muscle. Myoblasts

neg: Dystrophin X chromosome, named B006, appears to be an introgression from a Neanderthal-modern human mating. Dystrophin Dystrophin is a rod-shaped cytoplasmic protein, and a vital part of a protein complex that connects the cytoskeleton of a muscle fiber to the surrounding extracellular matrix through the cell membrane. This complex is variously known as the costamere or the dystrophin-associated protein complex (DAPC). Many muscle proteins, such as α-dystrobrevin, syncoilin, synemin, sarcoglycan, dystroglycan, and sarcospan, colocalize with dystrophin at the costamere. The DMD gene, encoding the dystrophin protein, is one of the longest human genes known, covering 2.3 megabases (0.08% of the human

neg: Sarcolemma smooth endoplasmic reticulum termed sarcoplasmatic reticulum (SR) in muscle. A transverse tubule surrounded by two SR cisternae are known as triads, and the contact between these structures is located at the junction of the A and I bands. Sarcolemma The sarcolemma ("sarco" (from "sarx") from Greek; flesh, and "lemma" from Greek; sheath) also called the myolemma, is the cell membrane of a striated muscle fiber cell. It consists of a lipid bilayer and a thin outer coat of polysaccharide material (glycocalyx) that contacts the basement membrane. The basement membrane contains numerous thin collagen fibrils and specialized proteins such as laminin

neg: Cardiac muscle L-type calcium channels triggers a much larger release of calcium from the sarcoplasmic reticulum in a phenomenon known as calcium-induced calcium release. In contrast, in skeletal muscle, minimal calcium flows into the cell during action potential and instead the sarcoplasmic reticulum in these cells is directly coupled to the surface membrane. This difference can be illustrated by the observation that cardiac muscle fibres require calcium to be present in the solution surrounding the cell in order to contract, while skeletal muscle fibres will contract without extracellular calcium. During contraction of a cardiac muscle cell, the long protein myofilaments oriented along

neg: Sarcoplasmic reticulum that there is a decrease in muscle contraction too. However, molecules such as adrenaline and noradrenaline, can prevent PLB from inhibiting SERCA. When these hormones bind to a receptor, called a beta 1 adrenoceptor, located on the cell membrane, they produce a series of reactions (known as a cyclic AMP pathway) that produces an enzyme called protein kinase A (PKA). PKA can add a phosphate to PLB (this is known as phosphorylation), preventing it from inhibiting SERCA and allowing for muscle relaxation. Located within the SR is a protein called calsequestrin. This protein can bind to around 50 Ca, which

neg: Samuel Victor Perry of the Royal Society, and contributed more than 300 scientific papers throughout his career. In 1984 he gave the Croonian Lecture on " Calcium and the regulation of contractile activity". After spending his postdoctoral period in America, Perry returned to Cambridge. Using his expertise in manipulating muscle tissue combined with his biochemical knowledge, he was able to isolate myofibril in an uncontracted state, and from that he was able to characterize their protein components. Further observation of the myofibrils, and the crude preparations of the extracted contractile protein actins and myosins taken from them, showed that they required trace levels

neg: GPR56 GPR56 G protein-coupled receptor 56 also known as TM7XN1 is a protein encoded by the "ADGRG1" gene. GPR56 is a member of the adhesion GPCR family. Adhesion GPCRs are characterized by an extended extracellular region often possessing N-terminal protein modules that is linked to a TM7 region via a domain known as the GPCR-Autoproteolysis INducing (GAIN) domain. GPR56 is expressed in liver, muscle, neural, and cytotoxic lymphoid cells in human as well as in hematopoietic precursor, muscle, and developing neural cells in the mouse. GPR56 has been shown to have numerous role in cell guidance/adhesion as exemplified by its roles

neg: Micro-g environment that the muscles are unloaded from carrying the weight of the human frame during space flight, whole muscle atrophy begins. Postural muscles contain more slow fibers, and are more prone to atrophy than non-postural muscle groups. The loss of muscle mass occurs because of imbalances in protein synthesis and breakdown. The loss of muscle mass is also accompanied by a loss of muscle strength, which was observed after only 2–5 days of spaceflight during the Soyuz-3 and Soyuz-8 missions. Decreases in the generation of contractile forces and whole muscle power have also been found in response to microgravity. To counter

neg: Dorothy M. Needham work of Otto Meyerhof. After that, she studied the roles of succinic acid, fumaric acid, and malic acid in muscle metabolism, as well as the biochemical differences and relationships between aerobic and anaerobic pathways. She subsequently worked on cyclic phosphate transfer in muscle contraction and, with collaborators, established for the first time a direct correlation of structure and function in muscle by confirming in 1939 that myosin, the contractile protein of muscle, behaves as the enzyme ATPase (adenosine triphosphatase). During World War II, Needham participated in research as a member of the chemical defence group led by Professor Malcolm Dixon

neg: Myostatin Myostatin Myostatin (also known as growth differentiation factor 8, abbreviated GDF-8) is a myokine, a protein produced and released by myocytes that acts on muscle cells' autocrine function to inhibit myogenesis: muscle cell growth and differentiation. In humans it is encoded by the "MSTN" gene. Myostatin is a secreted growth differentiation factor that is a member of the TGF beta protein family. Animals either lacking myostatin or treated with substances that block the activity of myostatin have significantly more muscle mass. Furthermore, individuals who have mutations in both copies of the myostatin gene have significantly more muscle mass and are

neg: Protein kinase B Protein kinase B Protein kinase B (PKB), also known as Akt, is a serine/threonine-specific protein kinase that plays a key role in multiple cellular processes such as glucose metabolism, apoptosis, cell proliferation, transcription and cell migration. Akt1 is involved in cellular survival pathways, by inhibiting apoptotic processes. Akt1 is also able to induce protein synthesis pathways, and is therefore a key signaling protein in the cellular pathways that lead to skeletal muscle hypertrophy, and general tissue growth. Mouse model with complete deletion of Akt1 manifests growth retardation and increased spontaneous apoptosis in tissues such as testes and thymus. Since it

neg: Protein kinase B major probably driver events in the pathogenesis of JGCTs. Protein kinase B Protein kinase B (PKB), also known as Akt, is a serine/threonine-specific protein kinase that plays a key role in multiple cellular processes such as glucose metabolism, apoptosis, cell proliferation, transcription and cell migration. Akt1 is involved in cellular survival pathways, by inhibiting apoptotic processes. Akt1 is also able to induce protein synthesis pathways, and is therefore a key signaling protein in the cellular pathways that lead to skeletal muscle hypertrophy, and general tissue growth. Mouse model with complete deletion of Akt1 manifests growth retardation and increased spontaneous apoptosis

neg: GLUT4 in increased skeletal muscle contraction. In skeletal muscle, muscle contractions increase GLUT4 translocation several fold, and this is likely regulated by RAC1 and AMP-activated protein kinase. Muscle stretching also stimulates GLUT4 translocation and glucose uptake in rodent muscle via RAC1. GLUT4 has been shown to interact with death-associated protein 6, also known as Daxx. Daxx, which is used to regulate apoptosis, has been shown to associate with GLUT4 in the cytoplasm. UBX-domains, such as the one found in GLUT4, have been shown to associate with apoptotic signaling. So this interaction aids in the translocation of Daxx within the cell. In

neg: Catecholaminergic polymorphic ventricular tachycardia arrhythmias that those with CPVT experience are caused by abnormalities in the way that cardiac muscle cells control their levels of calcium. Calcium interacts with the protein fibres or myofibrils inside the cell that allow the cell to contract, and the concentration of calcium within each cell needs to be very tightly regulated. During each heartbeat, the concentration of calcium must rise to allow the muscle to contract, and then fall to allow the muscle to relax, a process achieved by using a store within the cell known as the sarcoplasmic reticulum. At the start of each heartbeat, calcium is

neg: SORBS1 SORBS1 CAP/Ponsin protein, also known as Sorbin and SH3 domain-containing protein 1 is a protein that in humans is encoded by the "SORBS1" gene. CAP/Ponsin is part of a small family of adaptor proteins that regulate cell adhesion, growth factor signaling and cytoskeletal formation. CAP/Ponsin is mainly expressed in heart, skeletal muscle, liver, adipose tissue, and macrophages; in striated muscle tissue, CAP/Ponsin is localized to costamere structures. CAP/Ponsin may exist as thirteen alternatively-spliced isoforms, ranging from 81 kDa to 142 kDa. CAP/Ponsin is part of an adaptor protein family, of which ArgBP2 and vinexin are also a part. These proteins

neg: SORBS1 2 diabetes and obesity. SORBS1 has been shown to interact with: SORBS1 CAP/Ponsin protein, also known as Sorbin and SH3 domain-containing protein 1 is a protein that in humans is encoded by the "SORBS1" gene. CAP/Ponsin is part of a small family of adaptor proteins that regulate cell adhesion, growth factor signaling and cytoskeletal formation. CAP/Ponsin is mainly expressed in heart, skeletal muscle, liver, adipose tissue, and macrophages; in striated muscle tissue, CAP/Ponsin is localized to costamere structures. CAP/Ponsin may exist as thirteen alternatively-spliced isoforms, ranging from 81 kDa to 142 kDa. CAP/Ponsin is part of an adaptor protein family,

neg: Protein phosphatase 1 Protein phosphatase 1 Protein phosphatase 1 (PP1) belongs to a certain class of phosphatases known as protein serine/threonine phosphatases. This type of phosphatase includes metal-dependent protein phosphatases (PPMs) and aspartate-based phosphatases. PP1 has been found to be important in the control of glycogen metabolism, muscle contraction, cell progression, neuronal activities, splicing of RNA, mitosis, cell division, apoptosis, protein synthesis, and regulation of membrane receptors and channels. Each PP1 enzyme contains both a catalytic subunit and a regulatory subunit. The catalytic subunit consists of a 30-kD single-domain protein that can form complexes with other regulatory subunits. The catalytic subunit is highly

neg: MFGE8 phosphatidylserine (PS) binding domain, as well as an Arginine-Glycine-Aspartic acid motif, which enables the binding to integrins. MFGE8 binds PS, which is exposed on the surface of apoptotic cells. Opsonization of the apoptotic cells and binding to integrins on the surface of phagocytic cells, mediates the engulfment of the dead cell. MFGE8 Milk fat globule-EGF factor 8 protein (Mfge8), also known as lactadherin, is a protein which in humans is encoded by the "MFGE8" gene. Mfge8 is secreted protein found in vertebrates, including mammals as well as birds. MFGE8 may function as a cell adhesion protein to connect smooth muscle

neg: Optogenetics contractile forces relevant to cell migration, cell division and wound healing have been optogenetically manipulated. The field has not developed to the point where processes crucial to cellular and developmental biology and cell signaling including protein localization, post-translational modification and GTP loading can be consistently controlled via optogenetics. While this extension of optogenetics remains to be further investigated, there are various conceptual methodologies that may prove to immediately robust. There is a considerable body of literature outlining photosensitive proteins that have been utilized in cell signaling pathways. CRY2, LOV, DRONPA and PHYB are photosynthetic proteins involved in inducible protein association