A protein complex of actin and MYOSINS occurring in muscle. It is the essential contractile substance of muscle.
A diverse superfamily of proteins that function as translocating proteins. They share the common characteristics of being able to bind ACTINS and hydrolyze MgATP. Myosins generally consist of heavy chains which are involved in locomotion, and light chains which are involved in regulation. Within the structure of myosin heavy chain are three domains: the head, the neck and the tail. The head region of the heavy chain contains the actin binding domain and MgATPase domain which provides energy for locomotion. The neck region is involved in binding the light-chains. The tail region provides the anchoring point that maintains the position of the heavy chain. The superfamily of myosins is organized into structural classes based upon the type and arrangement of the subunits they contain.
The subfamily of myosin proteins that are commonly found in muscle fibers. Myosin II is also involved a diverse array of cellular functions including cell division, transport within the GOLGI APPARATUS, and maintaining MICROVILLI structure.
Filamentous proteins that are the main constituent of the thin filaments of muscle fibers. The filaments (known also as filamentous or F-actin) can be dissociated into their globular subunits; each subunit is composed of a single polypeptide 375 amino acids long. This is known as globular or G-actin. In conjunction with MYOSINS, actin is responsible for the contraction and relaxation of muscle.
Parts of the myosin molecule resulting from cleavage by proteolytic enzymes (PAPAIN; TRYPSIN; or CHYMOTRYPSIN) at well-localized regions. Study of these isolated fragments helps to delineate the functional roles of different parts of myosin. Two of the most common subfragments are myosin S-1 and myosin S-2. S-1 contains the heads of the heavy chains plus the light chains and S-2 contains part of the double-stranded, alpha-helical, heavy chain tail (myosin rod).
A protein found in the thin filaments of muscle fibers. It inhibits contraction of the muscle unless its position is modified by TROPONIN.
The process by which the CYTOPLASM of a cell is divided.
A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.
One of the minor protein components of skeletal muscle. Its function is to serve as the calcium-binding component in the troponin-tropomyosin B-actin-myosin complex by conferring calcium sensitivity to the cross-linked actin and myosin filaments.
The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.
A class of organic compounds containing four or more ring structures, one of which is made up of more than one kind of atom, usually carbon plus another atom. The heterocycle may be either aromatic or nonaromatic.
Fibers composed of MICROFILAMENT PROTEINS, which are predominately ACTIN. They are the smallest of the cytoskeletal filaments.
A nonmuscle isoform of myosin type II found predominantly in platelets, lymphocytes, neutrophils and brush border enterocytes.
The long cylindrical contractile organelles of STRIATED MUSCLE cells composed of ACTIN FILAMENTS; MYOSIN filaments; and other proteins organized in arrays of repeating units called SARCOMERES .
The network of filaments, tubules, and interconnecting filamentous bridges which give shape, structure, and organization to the cytoplasm.
Contractile tissue that produces movement in animals.
Proteins which bind calmodulin. They are found in many tissues and have a variety of functions including F-actin cross-linking properties, inhibition of cyclic nucleotide phosphodiesterase and calcium and magnesium ATPases.
A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.
'Gizzard', in a medical context, is a term rarely used but can refer to the muscular stomach of a bird, responsible for grinding and macerating food with the aid of ingested pebbles or grit.
The smaller subunits of MYOSINS that bind near the head groups of MYOSIN HEAVY CHAINS. The myosin light chains have a molecular weight of about 20 KDa and there are usually one essential and one regulatory pair of light chains associated with each heavy chain. Many myosin light chains that bind calcium are considered "calmodulin-like" proteins.
The quality of surface form or outline of CELLS.
An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.
The protein constituents of muscle, the major ones being ACTINS and MYOSINS. More than a dozen accessory proteins exist including TROPONIN; TROPOMYOSIN; and DYSTROPHIN.
1,N-6-Ethenoadenosine triphosphate. A fluorescent analog of adenosine triphosphate.
Adenosine 5'-(trihydrogen diphosphate). An adenine nucleotide containing two phosphate groups esterified to the sugar moiety at the 5'-position.
Proteins that are involved in or cause CELL MOVEMENT such as the rotary structures (flagellar motor) or the structures whose movement is directed along cytoskeletal filaments (MYOSIN; KINESIN; and DYNEIN motor families).
The formation of a solid in a solution as a result of a chemical reaction or the aggregation of soluble substances into complexes large enough to fall out of solution.
Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.
The larger subunits of MYOSINS. The heavy chains have a molecular weight of about 230 kDa and each heavy chain is usually associated with a dissimilar pair of MYOSIN LIGHT CHAINS. The heavy chains possess actin-binding and ATPase activity.
Bundles of actin filaments (ACTIN CYTOSKELETON) and myosin-II that span across the cell attaching to the cell membrane at FOCAL ADHESIONS and to the network of INTERMEDIATE FILAMENTS that surrounds the nucleus.
A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
The movement of CYTOPLASM within a CELL. It serves as an internal transport system for moving essential substances throughout the cell, and in single-celled organisms, such as the AMOEBA, it is responsible for the movement (CELL MOVEMENT) of the entire cell.
A group of intracellular-signaling serine threonine kinases that bind to RHO GTP-BINDING PROTEINS. They were originally found to mediate the effects of rhoA GTP-BINDING PROTEIN on the formation of STRESS FIBERS and FOCAL ADHESIONS. Rho-associated kinases have specificity for a variety of substrates including MYOSIN-LIGHT-CHAIN PHOSPHATASE and LIM KINASES.
The rate dynamics in chemical or physical systems.
A genus of ascomycetous fungi of the family Schizosaccharomycetaceae, order Schizosaccharomycetales.
Proteins obtained from the species Schizosaccharomyces pombe. The function of specific proteins from this organism are the subject of intense scientific interest and have been used to derive basic understanding of the functioning similar proteins in higher eukaryotes.
Very toxic polypeptide isolated mainly from AMANITA phalloides (Agaricaceae) or death cup; causes fatal liver, kidney and CNS damage in mushroom poisoning; used in the study of liver damage.
One of the three polypeptide chains that make up the TROPONIN complex. It inhibits F-actin-myosin interactions.
A nonmuscle isoform of myosin type II found predominantly in neuronal tissue.
Monomeric subunits of primarily globular ACTIN and found in the cytoplasmic matrix of almost all cells. They are often associated with microtubules and may play a role in cytoskeletal function and/or mediate movement of the cell or the organelles within the cell.
Orientation of intracellular structures especially with respect to the apical and basolateral domains of the plasma membrane. Polarized cells must direct proteins from the Golgi apparatus to the appropriate domain since tight junctions prevent proteins from diffusing between the two domains.
One of the three polypeptide chains that make up the TROPONIN complex of skeletal muscle. It is a calcium-binding protein.
Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)
An enzyme that phosphorylates myosin light chains in the presence of ATP to yield myosin-light chain phosphate and ADP, and requires calcium and CALMODULIN. The 20-kDa light chain is phosphorylated more rapidly than any other acceptor, but light chains from other myosins and myosin itself can act as acceptors. The enzyme plays a central role in the regulation of smooth muscle contraction.
Proteins which participate in contractile processes. They include MUSCLE PROTEINS as well as those found in other cells and tissues. In the latter, these proteins participate in localized contractile events in the cytoplasm, in motile activity, and in cell aggregation phenomena.
Recording serial images of a process at regular intervals spaced out over a longer period of time than the time in which the recordings will be played back.
A process of complicated morphogenetic cell movements that reorganizes a bilayer embryo into one with three GERM LAYERS and specific orientation (dorsal/ventral; anterior/posterior). Gastrulation describes the germ layer development of a non-mammalian BLASTULA or that of a mammalian BLASTOCYST.
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.
A powerful flexor of the thigh at the hip joint (psoas major) and a weak flexor of the trunk and lumbar spinal column (psoas minor). Psoas is derived from the Greek "psoa", the plural meaning "muscles of the loin". It is a common site of infection manifesting as abscess (PSOAS ABSCESS). The psoas muscles and their fibers are also used frequently in experiments in muscle physiology.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
Carrier of aroma of butter, vinegar, coffee, and other foods.
A plant family of the order Myrtales, subclass Rosidae, class Magnoliopsida that is a small family with a single genus.
A genus of protozoa, formerly also considered a fungus. Characteristics include the presence of violet to brown spores.
Muscular contractions characterized by increase in tension without change in length.

Evidence for F-actin-dependent and -independent mechanisms involved in assembly and stability of the medial actomyosin ring in fission yeast. (1/982)

Cell division in a number of eukaryotes, including the fission yeast Schizosaccharomyces pombe, is achieved through a medially placed actomyosin-based contractile ring. Although several components of the actomyosin ring have been identified, the mechanisms regulating ring assembly are still not understood. Here, we show by biochemical and mutational studies that the S.pombe actomyosin ring component Cdc4p is a light chain associated with Myo2p, a myosin II heavy chain. Localization of Myo2p to the medial ring depended on Cdc4p function, whereas localization of Cdc4p at the division site was independent of Myo2p. Interestingly, the actin-binding and motor domains of Myo2p are not required for its accumulation at the division site although the motor activity of Myo2p is essential for assembly of a normal actomyosin ring. The initial assembly of Myo2p and Cdc4p at the division site requires a functional F-actin cytoskeleton. Once established, however, F-actin is not required for the maintenance of Cdc4p and Myo2p medial rings, suggesting that the attachment of Cdc4p and Myo2p to the division site involves proteins other than actin itself.  (+info)

Calculation of a Gap restoration in the membrane skeleton of the red blood cell: possible role for myosin II in local repair. (2/982)

Human red blood cells contain all of the elements involved in the formation of nonmuscle actomyosin II complexes (V. M. Fowler. 1986. J. Cell. Biochem. 31:1-9; 1996. Curr. Opin. Cell Biol. 8:86-96). No clear function has yet been attributed to these complexes. Using a mathematical model for the structure of the red blood cell spectrin skeleton (M. J. Saxton. 1992. J. Theor. Biol. 155:517-536), we have explored a possible role for myosin II bipolar minifilaments in the restoration of the membrane skeleton, which may be locally damaged by major mechanical or chemical stress. We propose that the establishment of stable links between distant antiparallel actin protofilaments after a local myosin II activation may initiate the repair of the disrupted area. We show that it is possible to define conditions in which the calculated number of myosin II minifilaments bound to actin protofilaments is consistent with the estimated number of myosin II minifilaments present in the red blood cells. A clear restoration effect can be observed when more than 50% of the spectrin polymers of a defined area are disrupted. It corresponds to a significant increase in the spectrin density in the protein free region of the membrane. This may be involved in a more complex repair process of the red blood cell membrane, which includes the vesiculation of the bilayer and the compaction of the disassembled spectrin network.  (+info)

Ca2+ and cross-bridge-induced changes in troponin C in skinned skeletal muscle fibers: effects of force inhibition. (3/982)

Changes in skeletal troponin C (sTnC) structure during thin filament activation by Ca2+ and strongly bound cross-bridge states were monitored by measuring the linear dichroism of the 5' isomer of iodoacetamidotetramethylrhodamine (5'IATR), attached to Cys98 (sTnC-5'ATR), in sTnC-5'ATR reconstituted single skinned fibers from rabbit psoas muscle. To isolate the effects of Ca2+ and cross-bridge binding on sTnC structure, maximum Ca2+-activated force was inhibited with 0.5 mM AlF4- or with 30 mM 2,3 butanedione-monoxime (BDM) during measurements of the Ca2+ dependence of force and dichroism. Dichroism was 0.08 +/- 0.01 (+/- SEM, n = 9) in relaxing solution (pCa 9.2) and decreased to 0.004 +/- 0.002 (+/- SEM, n = 9) at pCa 4.0. Force and dichroism had similar Ca2+ sensitivities. Force inhibition with BDM caused no change in the amplitude and Ca2+ sensitivity of dichroism. Similarly, inhibition of force at pCa 4.0 with 0.5 mM AlF4- decreased force to 0.04 +/- 0.01 of maximum (+/- SEM, n = 3), and dichroism was 0.04 +/- 0.03 (+/- SEM, n = 3) of the value at pCa 9.2 and unchanged relative to the corresponding normalized value at pCa 4.0 (0.11 +/- 0.05, +/- SEM; n = 3). Inhibition of force with AlF4- also had no effect when sTnC structure was monitored by labeling with either 5-dimethylamino-1-napthalenylsulfonylaziridine (DANZ) or 4-(N-(iodoacetoxy)ethyl-N-methyl)amino-7-nitrobenz-2-oxa-1,3-diazole (NBD). Increasing sarcomere length from 2.5 to 3.6 microm caused force (pCa 4.0) to decrease, but had no effect on dichroism. In contrast, rigor cross-bridge attachment caused dichroism at pCa 9.2 to decrease to 0.56 +/- 0.03 (+/- SEM, n = 5) of the value at pCa 9. 2, and force was 0.51 +/- 0.04 (+/- SEM, n = 6) of pCa 4.0 control. At pCa 4.0 in rigor, dichroism decreased further to 0.19 +/- 0.03 (+/- SEM, n = 6), slightly above the pCa 4.0 control level; force was 0.66 +/- 0.04 of pCa 4.0 control. These results indicate that cross-bridge binding in the rigor state alters sTnC structure, whereas cycling cross-bridges have little influence at either submaximum or maximum activating [Ca2+].  (+info)

Rational analyses of organelle trajectories in tobacco pollen tubes reveal characteristics of the actomyosin cytoskeleton. (4/982)

To gain insight into the characteristics of organelle movement and the underlying actomyosin motility system in tobacco pollen tubes, we collected data points representing sequential organelle positions in control and cytochalasin-treated cells, and in a sample of extruded cytoplasm. These data were utilized to reconstruct approximately 900 tracks, representing individual organelle movements, and to produce a quantitative analysis of the movement properties, supported by statistical tests. Each reconstructed track appeared to be unique and to show irregularities in velocity and direction of movement. The regularity quotient was near 2 at the tip and above 3 elsewhere in the cell, indicating that movement is more vectorial in the tube area. Similarly, the progressiveness ratio showed that there were relatively more straight trajectories in the tube region than at the tip. Consistent with these data, arithmetical dissection revealed a high degree of randomlike movement in the apex, lanes with tip-directed movement along the flanks, and grain-directed movement in the center of the tube. Intercalated lanes with bidirectional movement had lower organelle velocity, suggesting that steric hindrance plays a role. The results from the movement analysis indicate that the axial arrangement of the actin filaments and performance of the actomyosin system increases from tip to base, and that the opposite polarity of the actin filaments in the peripheral (+-ends of acting filaments toward the tip) versus the central cytoplasm (+-ends of actin filaments toward to the grain) is installed within a few minutes in these tip-growing cells.  (+info)

Alterations of cross-bridge kinetics in human atrial and ventricular myocardium. (5/982)

CONDENSED ABSTRACT: We analyzed actomyosin cross-bridge kinetics in human atrial and ventricular muscle strip preparations by using sinusoidal length changes from 0.1 to 60 Hz. The minimum stiffness frequency was higher in atrial than in ventricular human myocardium and lower in failing than in non-failing left ventricular human myocardium. beta-Adrenergic stimulation increased the minimum stiffness frequency by 18 +/- 3% (p < 0.05). Cross-bridge kinetics are temperature-dependent, with a Q10 of at least 2.7. BACKGROUND: Dynamic stiffness measurements have revealed acute and chronic alterations of actomyosin cross-bridge kinetics in cardiac muscles of a variety of different animal species. We studied dynamic stiffness in right atrial and left ventricular preparations of non-failing and failing human hearts and tested the influence of the temperature and beta-adrenergic stimulation on cross-bridge kinetics. METHODS AND RESULTS: Muscle strips were prepared from right atria and left ventricles from human non-failing and failing hearts. After withdrawal of calcium, steady contracture tension was induced by the addition of 1.5 mM barium chloride. Sinusoidal length oscillations of 1% muscle length were applied, with a frequency spectrum of between 0.1 and 60 Hz. Dynamic stiffness was calculated from the length change and the corresponding force response amplitude. The specific minimum stiffness frequency, which indicates the interaction between cross-bridge recruitment and cross-bridge cycling dynamics, was analyzed for each condition: (1) The minimum stiffness frequency was 0.78 +/- 0.04 Hz in left ventricular myocardium and 2.80 +/- 0.31 Hz in right atrial myocardium (p < 0.01) at 27 degrees C. (2) The minimum stiffness frequency was 41% higher in non-failing compared to failing left ventricular human myocardium. (3) Over a wide range of experimental temperatures, the minimum stiffness frequency changed, with a Q10 of at least 2.7. (4) beta-Adrenergic stimulation significantly (p < 0.05) increased the minimum stiffness to 18 +/- 3% higher frequencies and significantly (p < 0.05) lowered contracture tension by 7 +/- 1%. CONCLUSIONS: The contractility of human heart muscle is not only regulated by excitation-contraction coupling but also by modulation of intrinsic properties of the actomyosin system. Acute and chronic alterations of cross-bridge kinetics have been demonstrated, which play a significant role in the physiology and pathophysiology of the human heart.  (+info)

Amphidinolide B, a powerful activator of actomyosin ATPase enhances skeletal muscle contraction. (6/982)

Amphidinolide B caused a concentration-dependent increase in the contractile force of skeletal muscle skinned fibers. The concentration-contractile response curve for external Ca2+ was shifted to the left in a parallel manner, suggesting an increase in Ca2+ sensitivity. Amphidinolide B stimulated the superprecipitation of natural actomyosin. The maximum response of natural actomyosin to Ca2+ in superprecipitation was enhanced by it. Amphidinolide B increased the ATPase activity of myofibrils and natural actomyosin. The ATPase activity of actomyosin reconstituted from actin and myosin was enhanced in a concentration-dependent manner in the presence or absence of troponin-tropomyosin complex. Ca2+-, K+-EDTA- or Mg2+-ATPase of myosin was not affected by amphidinolide B. These results suggest that amphidinolide B enhances an interaction of actin and myosin directly and increases Ca2+ sensitivity of the contractile apparatus mediated through troponin-tropomyosin system, resulting in an increase in the ATPase activity of actomyosin and thus enhances the contractile response of myofilament.  (+info)

Backward movements of cross-bridges by application of stretch and by binding of MgADP to skeletal muscle fibers in the rigor state as studied by x-ray diffraction. (7/982)

The effects of the applied stretch and MgADP binding on the structure of the actomyosin cross-bridges in rabbit and/or frog skeletal muscle fibers in the rigor state have been investigated with improved resolution by x-ray diffraction using synchrotron radiation. The results showed a remarkable structural similarity between cross-bridge states induced by stretch and MgADP binding. The intensities of the 14.4- and 7.2-nm meridional reflections increased by approximately 23 and 47%, respectively, when 1 mM MgADP was added to the rigor rabbit muscle fibers in the presence of ATP-depletion backup system and an inhibitor for muscle adenylate kinase or by approximately 33 and 17%, respectively, when rigor frog muscle was stretched by approximately 4.5% of the initial muscle length. In addition, both MgADP binding and stretch induced a small but genuine intensity decrease in the region close to the meridian of the 5.9-nm layer line while retaining the intensity profile of its outer portion. No appreciable influence was observed in the intensities of the higher order meridional reflections of the 14.4-nm repeat and the other actin-based reflections as well as the equatorial reflections, indicating a lack of detachment of cross-bridges in both cases. The changes in the axial spacings of the actin-based and the 14.4-nm-based reflections were observed and associated with the tension change. These results indicate that stretch and ADP binding mediate similar structural changes, being in the correct direction to those expected for that the conformational changes are induced in the outer portion distant from the catalytic domain of attached cross-bridges. Modeling of conformational changes of the attached myosin head suggested a small but significant movement (about 10-20 degrees) in the light chain-binding domain of the head toward the M-line of the sarcomere. Both chemical (ADP binding) and mechanical (stretch) intervensions can reverse the contractile cycle by causing a backward movement of this domain of attached myosin heads in the rigor state.  (+info)

The translation in vitro of mRNA from developing cysts of Artemia salina. (8/982)

Successive stages in the development of the brine shrimp cyst were used as a model for studying differentiation at the level of mRNA transcription and translation. The poly (A)-containing mRNA from dormant cysts and free-swimming larvae (nauplii) was found to be efficiently translated in a wheat-germ cell-free system, and electrophoretic patterns of translation products in vitro resembled those of the endogenous proteins extracted from the equivalent developmental stages. Each stage, however, exhibits a characteristic protein pattern. Two low-molecular-weight proteins prominent in the cyst disappeared almost completely in the nauplius stage, whereas the proportion of actin increased 3-fold. Parallel patterns were observed upon translation in vitro of the respective mRNA preparations. The percentage of the acidic protein, tubulin, decreased somewhat during development.  (+info)

Actomyosin is a contractile protein complex that consists of actin and myosin filaments. It plays an essential role in muscle contraction, cell motility, and cytokinesis (the process of cell division where the cytoplasm is divided into two daughter cells). The interaction between actin and myosin generates force and movement through a mechanism called sliding filament theory. In this process, myosin heads bind to actin filaments and then undergo a power stroke, which results in the sliding of one filament relative to the other and ultimately leads to muscle contraction or cellular movements. Actomyosin complexes are also involved in various non-muscle cellular processes such as cytoplasmic streaming, intracellular transport, and maintenance of cell shape.

Myosins are a large family of motor proteins that play a crucial role in various cellular processes, including muscle contraction and intracellular transport. They consist of heavy chains, which contain the motor domain responsible for generating force and motion, and light chains, which regulate the activity of the myosin. Based on their structural and functional differences, myosins are classified into over 35 classes, with classes II, V, and VI being the most well-studied.

Class II myosins, also known as conventional myosins, are responsible for muscle contraction in skeletal, cardiac, and smooth muscles. They form filaments called thick filaments, which interact with actin filaments to generate force and movement during muscle contraction.

Class V myosins, also known as unconventional myosins, are involved in intracellular transport and organelle positioning. They have a long tail that can bind to various cargoes, such as vesicles, mitochondria, and nuclei, and a motor domain that moves along actin filaments to transport the cargoes to their destinations.

Class VI myosins are also unconventional myosins involved in intracellular transport and organelle positioning. They have two heads connected by a coiled-coil tail, which can bind to various cargoes. Class VI myosins move along actin filaments in a unique hand-over-hand motion, allowing them to transport their cargoes efficiently.

Overall, myosins are essential for many cellular functions and have been implicated in various diseases, including cardiovascular diseases, neurological disorders, and cancer.

Myosin Type II, also known as myosin II or heavy meromyosin, is a type of motor protein involved in muscle contraction and other cellular movements. It is a hexameric protein composed of two heavy chains and four light chains. The heavy chains have a head domain that binds to actin filaments and an tail domain that forms a coiled-coil structure, allowing the formation of filaments. Myosin II uses the energy from ATP hydrolysis to move along actin filaments, generating force and causing muscle contraction or other cell movements. It plays a crucial role in various cellular processes such as cytokinesis, cell motility, and maintenance of cell shape.

Actin is a type of protein that forms part of the contractile apparatus in muscle cells, and is also found in various other cell types. It is a globular protein that polymerizes to form long filaments, which are important for many cellular processes such as cell division, cell motility, and the maintenance of cell shape. In muscle cells, actin filaments interact with another type of protein called myosin to enable muscle contraction. Actins can be further divided into different subtypes, including alpha-actin, beta-actin, and gamma-actin, which have distinct functions and expression patterns in the body.

Myosin subfragments refer to the smaller components that result from the dissociation or proteolytic digestion of myosin, a motor protein involved in muscle contraction. The two main subfragments are called S1 and S2.

S1 is the "head" of the myosin molecule, which contains the actin-binding site, ATPase activity, and the ability to generate force and motion during muscle contraction. It has a molecular weight of approximately 120 kDa.

S2 is the "tail" of the myosin molecule, which has a molecular weight of about 350 kDa and is responsible for forming the backbone of the thick filament in muscle sarcomeres. S2 can be further divided into light meromyosin (LMM) and heavy meromyosin (HMM). HMM consists of S1 and part of S2, while LMM comprises the remaining portion of S2.

These subfragments are essential for understanding myosin's structure, function, and interactions with other muscle components at a molecular level.

Tropomyosin is a protein that plays a crucial role in muscle contraction. It is a long, thin filamentous protein that runs along the length of actin filaments in muscle cells, forming part of the troponin-tropomyosin complex. This complex regulates the interaction between actin and myosin, which are the other two key proteins involved in muscle contraction.

In a relaxed muscle, tropomyosin blocks the myosin-binding sites on actin, preventing muscle contraction from occurring. When a signal is received to contract, calcium ions are released into the muscle cell, which binds to troponin and causes a conformational change that moves tropomyosin out of the way, exposing the myosin-binding sites on actin. This allows myosin to bind to actin and generate force, leading to muscle contraction.

Tropomyosin is composed of two alpha-helical chains that wind around each other in a coiled-coil structure. There are several isoforms of tropomyosin found in different types of muscle cells, including skeletal, cardiac, and smooth muscle. Mutations in the genes encoding tropomyosin have been associated with various inherited muscle disorders, such as hypertrophic cardiomyopathy and distal arthrogryposis.

Cytokinesis is the part of the cell division process (mitosis or meiosis) in which the cytoplasm of a single eukaryotic cell divides into two daughter cells. It usually begins after telophase, and it involves the constriction of a contractile ring composed of actin filaments and myosin motor proteins that forms at the equatorial plane of the cell. This results in the formation of a cleavage furrow, which deepens and eventually leads to the physical separation of the two daughter cells. Cytokinesis is essential for cell reproduction and growth in multicellular organisms, and its failure can lead to various developmental abnormalities or diseases.

Adenosine triphosphatases (ATPases) are a group of enzymes that catalyze the conversion of adenosine triphosphate (ATP) into adenosine diphosphate (ADP) and inorganic phosphate. This reaction releases energy, which is used to drive various cellular processes such as muscle contraction, transport of ions across membranes, and synthesis of proteins and nucleic acids.

ATPases are classified into several types based on their structure, function, and mechanism of action. Some examples include:

1. P-type ATPases: These ATPases form a phosphorylated intermediate during the reaction cycle and are involved in the transport of ions across membranes, such as the sodium-potassium pump and calcium pumps.
2. F-type ATPases: These ATPases are found in mitochondria, chloroplasts, and bacteria, and are responsible for generating a proton gradient across the membrane, which is used to synthesize ATP.
3. V-type ATPases: These ATPases are found in vacuolar membranes and endomembranes, and are involved in acidification of intracellular compartments.
4. A-type ATPases: These ATPases are found in the plasma membrane and are involved in various functions such as cell signaling and ion transport.

Overall, ATPases play a crucial role in maintaining the energy balance of cells and regulating various physiological processes.

Troponin is a protein complex found in cardiac and skeletal muscle cells that plays a critical role in muscle contraction. It consists of three subunits: troponin C, which binds calcium ions; troponin I, which inhibits the interaction between actin and myosin in the absence of calcium; and troponin T, which binds to tropomyosin and helps anchor the complex to the muscle filament.

In clinical medicine, "troponin" usually refers to cardiac-specific isoforms of these proteins (cTnI and cTnT) that are released into the bloodstream following damage to the heart muscle, such as occurs in myocardial infarction (heart attack). Measurement of troponin levels in the blood is a sensitive and specific biomarker for the diagnosis of acute myocardial infarction.

I believe there may be some confusion in your question. "Rabbits" is a common name used to refer to the Lagomorpha species, particularly members of the family Leporidae. They are small mammals known for their long ears, strong legs, and quick reproduction.

However, if you're referring to "rabbits" in a medical context, there is a term called "rabbit syndrome," which is a rare movement disorder characterized by repetitive, involuntary movements of the fingers, resembling those of a rabbit chewing. It is also known as "finger-chewing chorea." This condition is usually associated with certain medications, particularly antipsychotics, and typically resolves when the medication is stopped or adjusted.

Heterocyclic compounds with 4 or more rings refer to a class of organic compounds that contain at least four aromatic or non-aromatic rings in their structure, where one or more of the rings contains atoms other than carbon (heteroatoms) such as nitrogen, oxygen, sulfur, or selenium. These compounds are widely found in nature and have significant importance in medicinal chemistry due to their diverse biological activities. Many natural and synthetic drugs, pigments, vitamins, and antibiotics contain heterocyclic structures with four or more rings. The properties of these compounds depend on the size, shape, and nature of the rings, as well as the presence and position of functional groups.

The actin cytoskeleton is a complex, dynamic network of filamentous (threadlike) proteins that provides structural support and shape to cells, allows for cell movement and division, and plays a role in intracellular transport. Actin filaments are composed of actin monomers that polymerize to form long, thin fibers. These filaments can be organized into different structures, such as stress fibers, which provide tension and support, or lamellipodia and filopodia, which are involved in cell motility. The actin cytoskeleton is constantly remodeling in response to various intracellular and extracellular signals, allowing for changes in cell shape and behavior.

Nonmuscle Myosin Type IIA (NMIIA) is a type of non-muscle myosin protein that belongs to the myosin II family. These motor proteins are responsible for generating contractile forces in non-muscle cells, which allows them to change shape and move. NMIIA is widely expressed in various tissues and plays crucial roles in numerous cellular processes, including cytokinesis (cell division), maintenance of cell shape, and intracellular transport.

NMIIA consists of two heavy chains, two regulatory light chains, and two essential light chains. The heavy chains have a motor domain that binds to actin filaments and hydrolyzes ATP to generate force for movement along the actin filament. The regulatory and essential light chains regulate the activity and assembly of NMIIA.

Mutations in the gene encoding NMIIA (MYH9) have been associated with several human genetic disorders, such as May-Hegglin anomaly, Fechtner syndrome, and Delletten-Patterson syndrome, which are characterized by thrombocytopenia, bleeding disorders, and hearing loss.

Myofibrils are the basic contractile units of muscle fibers, composed of highly organized arrays of thick and thin filaments. They are responsible for generating the force necessary for muscle contraction. The thick filaments are primarily made up of the protein myosin, while the thin filaments are mainly composed of actin. Myofibrils are surrounded by a membrane called the sarcolemma and are organized into repeating sections called sarcomeres, which are the functional units of muscle contraction.

The cytoskeleton is a complex network of various protein filaments that provides structural support, shape, and stability to the cell. It plays a crucial role in maintaining cellular integrity, intracellular organization, and enabling cell movement. The cytoskeleton is composed of three major types of protein fibers: microfilaments (actin filaments), intermediate filaments, and microtubules. These filaments work together to provide mechanical support, participate in cell division, intracellular transport, and help maintain the cell's architecture. The dynamic nature of the cytoskeleton allows cells to adapt to changing environmental conditions and respond to various stimuli.

A muscle is a soft tissue in our body that contracts to produce force and motion. It is composed mainly of specialized cells called muscle fibers, which are bound together by connective tissue. There are three types of muscles: skeletal (voluntary), smooth (involuntary), and cardiac. Skeletal muscles attach to bones and help in movement, while smooth muscles are found within the walls of organs and blood vessels, helping with functions like digestion and circulation. Cardiac muscle is the specific type that makes up the heart, allowing it to pump blood throughout the body.

Calmodulin-binding proteins are a diverse group of proteins that have the ability to bind to calmodulin, a ubiquitous calcium-binding protein found in eukaryotic cells. Calmodulin plays a critical role in various cellular processes by regulating the activity of its target proteins in a calcium-dependent manner.

Calmodulin-binding proteins contain specific domains or motifs that enable them to interact with calmodulin. These domains can be classified into two main categories: IQ motifs and CaM motifs. The IQ motif is a short amino acid sequence that contains the consensus sequence IQXXXRGXXR, where X represents any amino acid. This motif binds to the C-lobe of calmodulin in a calcium-dependent manner. On the other hand, CaM motifs are longer sequences that can bind to both lobes of calmodulin with high affinity and in a calcium-dependent manner.

Calmodulin-binding proteins play crucial roles in various cellular functions, including signal transduction, gene regulation, cytoskeleton organization, and ion channel regulation. For example, calmodulin-binding proteins such as calcineurin and CaM kinases are involved in the regulation of immune responses, learning, and memory. Similarly, myosin regulatory light chains, which contain IQ motifs, play a critical role in muscle contraction by regulating the interaction between actin and myosin filaments.

In summary, calmodulin-binding proteins are a diverse group of proteins that interact with calmodulin to regulate various cellular processes. They contain specific domains or motifs that enable them to bind to calmodulin in a calcium-dependent manner, thereby modulating the activity of their target proteins.

Muscle contraction is the physiological process in which muscle fibers shorten and generate force, leading to movement or stability of a body part. This process involves the sliding filament theory where thick and thin filaments within the sarcomeres (the functional units of muscles) slide past each other, facilitated by the interaction between myosin heads and actin filaments. The energy required for this action is provided by the hydrolysis of adenosine triphosphate (ATP). Muscle contractions can be voluntary or involuntary, and they play a crucial role in various bodily functions such as locomotion, circulation, respiration, and posture maintenance.

In human anatomy, a "gizzard" does not exist as it is not part of the human digestive system. However, in veterinary medicine, the gizzard refers to a part of the stomach in birds and some other animals, such as crocodiles and alligators. It is a muscular, thick-walled portion where food is stored and mechanically broken down by grinding and mixing it with grit that the animal has swallowed. This action helps in the digestion process, especially for birds that do not have teeth to chew their food.

Myosin light chains are regulatory proteins that bind to the myosin head region of myosin molecules, which are involved in muscle contraction. There are two types of myosin light chains, essential and regulatory, that have different functions. The essential light chains are necessary for the assembly and stability of the myosin filaments, while the regulatory light chains control the calcium-sensitive activation of the myosin ATPase activity during muscle contraction. Phosphorylation of the regulatory light chains plays a critical role in regulating muscle contraction and relaxation.

Cell shape refers to the physical form or configuration of a cell, which is determined by the cytoskeleton (the internal framework of the cell) and the extracellular matrix (the external environment surrounding the cell). The shape of a cell can vary widely depending on its type and function. For example, some cells are spherical, such as red blood cells, while others are elongated or irregularly shaped. Changes in cell shape can be indicative of various physiological or pathological processes, including development, differentiation, migration, and disease.

Adenosine Triphosphate (ATP) is a high-energy molecule that stores and transports energy within cells. It is the main source of energy for most cellular processes, including muscle contraction, nerve impulse transmission, and protein synthesis. ATP is composed of a base (adenine), a sugar (ribose), and three phosphate groups. The bonds between these phosphate groups contain a significant amount of energy, which can be released when the bond between the second and third phosphate group is broken, resulting in the formation of adenosine diphosphate (ADP) and inorganic phosphate. This process is known as hydrolysis and can be catalyzed by various enzymes to drive a wide range of cellular functions. ATP can also be regenerated from ADP through various metabolic pathways, such as oxidative phosphorylation or substrate-level phosphorylation, allowing for the continuous supply of energy to cells.

Muscle proteins are a type of protein that are found in muscle tissue and are responsible for providing structure, strength, and functionality to muscles. The two major types of muscle proteins are:

1. Contractile proteins: These include actin and myosin, which are responsible for the contraction and relaxation of muscles. They work together to cause muscle movement by sliding along each other and shortening the muscle fibers.
2. Structural proteins: These include titin, nebulin, and desmin, which provide structural support and stability to muscle fibers. Titin is the largest protein in the human body and acts as a molecular spring that helps maintain the integrity of the sarcomere (the basic unit of muscle contraction). Nebulin helps regulate the length of the sarcomere, while desmin forms a network of filaments that connects adjacent muscle fibers together.

Overall, muscle proteins play a critical role in maintaining muscle health and function, and their dysregulation can lead to various muscle-related disorders such as muscular dystrophy, myopathies, and sarcopenia.

I'm sorry for any confusion, but "Ethenoadenosine Triphosphate" is not a recognized medical term or a valid chemical compound. It seems that this term may be a combination of two different terms: "ethylene" and "adenosine triphosphate (ATP)."

Ethylene is a hydrocarbon gas with the formula C2H4, while adenosine triphosphate (ATP) is a complex organic chemical that provides energy to all the cells in our body. ATP is often referred to as the "molecular unit of currency" of intracellular energy transfer.

If you have any questions about these or other medical or scientific topics, please don't hesitate to ask!

Adenosine diphosphate (ADP) is a chemical compound that plays a crucial role in energy transfer within cells. It is a nucleotide, which consists of a adenosine molecule (a sugar molecule called ribose attached to a nitrogenous base called adenine) and two phosphate groups.

In the cell, ADP functions as an intermediate in the conversion of energy from one form to another. When a high-energy phosphate bond in ADP is broken, energy is released and ADP is converted to adenosine triphosphate (ATP), which serves as the main energy currency of the cell. Conversely, when ATP donates a phosphate group to another molecule, it is converted back to ADP, releasing energy for the cell to use.

ADP also plays a role in blood clotting and other physiological processes. In the coagulation cascade, ADP released from damaged red blood cells can help activate platelets and initiate the formation of a blood clot.

Molecular motor proteins are a type of protein that convert chemical energy into mechanical work at the molecular level. They play a crucial role in various cellular processes, such as cell division, muscle contraction, and intracellular transport. There are several types of molecular motor proteins, including myosin, kinesin, and dynein.

Myosin is responsible for muscle contraction and movement along actin filaments in the cytoplasm. Kinesin and dynein are involved in intracellular transport along microtubules, moving cargo such as vesicles, organelles, and mRNA to various destinations within the cell.

These motor proteins move in a stepwise fashion, with each step driven by the hydrolysis of adenosine triphosphate (ATP) into adenosine diphosphate (ADP) and inorganic phosphate (Pi). The directionality and speed of movement are determined by the structure and regulation of the motor proteins, as well as the properties of the tracks along which they move.

Chemical precipitation is a process in which a chemical compound becomes a solid, insoluble form, known as a precipitate, from a liquid solution. This occurs when the concentration of the compound in the solution exceeds its solubility limit and forms a separate phase. The reaction that causes the formation of the precipitate can be a result of various factors such as changes in temperature, pH, or the addition of another chemical reagent.

In the medical field, chemical precipitation is used in diagnostic tests to detect and measure the presence of certain substances in body fluids, such as blood or urine. For example, a common test for kidney function involves adding a chemical reagent to a urine sample, which causes the excess protein in the urine to precipitate out of solution. The amount of precipitate formed can then be measured and used to diagnose and monitor kidney disease.

Chemical precipitation is also used in the treatment of certain medical conditions, such as heavy metal poisoning. In this case, a chelating agent is administered to bind with the toxic metal ions in the body, forming an insoluble compound that can be excreted through the urine or feces. This process helps to reduce the amount of toxic metals in the body and alleviate symptoms associated with poisoning.

"Chickens" is a common term used to refer to the domesticated bird, Gallus gallus domesticus, which is widely raised for its eggs and meat. However, in medical terms, "chickens" is not a standard term with a specific definition. If you have any specific medical concern or question related to chickens, such as food safety or allergies, please provide more details so I can give a more accurate answer.

Myosin Heavy Chains are the large, essential components of myosin molecules, which are responsible for the molecular motility in muscle cells. These heavy chains have a molecular weight of approximately 200 kDa and form the motor domain of myosin, which binds to actin filaments and hydrolyzes ATP to generate force and movement during muscle contraction. There are several different types of myosin heavy chains, each with specific roles in various tissues and cellular functions. In skeletal and cardiac muscles, for example, myosin heavy chains have distinct isoforms that contribute to the contractile properties of these tissues.

Stress fibers are specialized cytoskeletal structures composed primarily of actin filaments, along with myosin II and other associated proteins. They are called "stress" fibers because they are thought to provide cells with the ability to resist and respond to mechanical stresses. These structures play a crucial role in maintaining cell shape, facilitating cell migration, and mediating cell-cell and cell-matrix adhesions. Stress fibers form bundles that span the length of the cell and connect to focal adhesion complexes at their ends, allowing for the transmission of forces between the extracellular matrix and the cytoskeleton. They are dynamic structures that can undergo rapid assembly and disassembly in response to various stimuli, including changes in mechanical stress, growth factor signaling, and cellular differentiation.

Calcium is an essential mineral that is vital for various physiological processes in the human body. The medical definition of calcium is as follows:

Calcium (Ca2+) is a crucial cation and the most abundant mineral in the human body, with approximately 99% of it found in bones and teeth. It plays a vital role in maintaining structural integrity, nerve impulse transmission, muscle contraction, hormonal secretion, blood coagulation, and enzyme activation.

Calcium homeostasis is tightly regulated through the interplay of several hormones, including parathyroid hormone (PTH), calcitonin, and vitamin D. Dietary calcium intake, absorption, and excretion are also critical factors in maintaining optimal calcium levels in the body.

Hypocalcemia refers to low serum calcium levels, while hypercalcemia indicates high serum calcium levels. Both conditions can have detrimental effects on various organ systems and require medical intervention to correct.

Cytoplasmic streaming, also known as cyclosis, is the movement or flow of cytoplasm and organelles within a eukaryotic cell. It is a type of intracellular transport that occurs in many types of cells, but it is particularly prominent in large, single-celled organisms such as algae and fungi.

During cytoplasmic streaming, the cytoplasm moves in a coordinated and organized manner, often in circular or spiral patterns. This movement is driven by the action of motor proteins, such as myosin, which interact with filamentous structures called actin filaments. The movement of the motor proteins along the actin filaments generates force, causing the cytoplasm and organelles to move.

Cytoplasmic streaming serves several functions in cells. It helps to distribute nutrients and metabolic products throughout the cell, and it also plays a role in the movement of organelles and other cellular components to specific locations within the cell. Additionally, cytoplasmic streaming can help to maintain the structural integrity of large, single-celled organisms by ensuring that their cytoplasm is evenly distributed.

Rho-associated kinases (ROCKs) are serine/threonine kinases that are involved in the regulation of various cellular processes, including actin cytoskeleton organization, cell migration, and gene expression. They are named after their association with the small GTPase RhoA, which activates them upon binding.

ROCKs exist as two isoforms, ROCK1 and ROCK2, which share a high degree of sequence homology and have similar functions. They contain several functional domains, including a kinase domain, a coiled-coil region that mediates protein-protein interactions, and a Rho-binding domain (RBD) that binds to active RhoA.

Once activated by RhoA, ROCKs phosphorylate a variety of downstream targets, including myosin light chain (MLC), LIM kinase (LIMK), and moesin, leading to the regulation of actomyosin contractility, stress fiber formation, and focal adhesion turnover. Dysregulation of ROCK signaling has been implicated in various pathological conditions, such as cancer, cardiovascular diseases, neurological disorders, and fibrosis. Therefore, ROCKs have emerged as promising therapeutic targets for the treatment of these diseases.

In the context of medicine and pharmacology, "kinetics" refers to the study of how a drug moves throughout the body, including its absorption, distribution, metabolism, and excretion (often abbreviated as ADME). This field is called "pharmacokinetics."

1. Absorption: This is the process of a drug moving from its site of administration into the bloodstream. Factors such as the route of administration (e.g., oral, intravenous, etc.), formulation, and individual physiological differences can affect absorption.

2. Distribution: Once a drug is in the bloodstream, it gets distributed throughout the body to various tissues and organs. This process is influenced by factors like blood flow, protein binding, and lipid solubility of the drug.

3. Metabolism: Drugs are often chemically modified in the body, typically in the liver, through processes known as metabolism. These changes can lead to the formation of active or inactive metabolites, which may then be further distributed, excreted, or undergo additional metabolic transformations.

4. Excretion: This is the process by which drugs and their metabolites are eliminated from the body, primarily through the kidneys (urine) and the liver (bile).

Understanding the kinetics of a drug is crucial for determining its optimal dosing regimen, potential interactions with other medications or foods, and any necessary adjustments for special populations like pediatric or geriatric patients, or those with impaired renal or hepatic function.

I apologize for any confusion, but "Schizosaccharomyces" is not a medical term. It is a genus name in the field of microbiology and genetics, referring to a group of budding, tear-shaped yeasts that are widely used as model organisms in scientific research. The most well-known species within this genus is Schizosaccharomyces pombe, which has been extensively studied for its cell cycle regulation, DNA repair mechanisms, and other fundamental biological processes.

If you have any questions related to medical terminology or health-related topics, I would be happy to help.

I'm sorry for any confusion, but "Schizosaccharomyces pombe proteins" is not a medical term or concept. Schizosaccharomyces pombe is a type of single-celled microorganism called a yeast, which is often used as a model organism in scientific research. Proteins are complex molecules that do most of the work in cells and are necessary for the structure, function, and regulation of the body's tissues and organs.

In the context of scientific research, "Schizosaccharomyces pombe proteins" would refer to the specific proteins found in or studied using this particular type of yeast. These proteins may have similarities to human proteins and can be used to help understand basic biological processes, as well as diseases that occur in humans. However, it is important to note that while research using model organisms like Schizosaccharomyces pombe has led to many important discoveries, the findings may not always translate directly to humans.

Phalloidine is not a medical term, but it is often referenced in the field of toxicology and mycology. Phalloidine is a toxin found in certain species of mushrooms, including the death cap (Amanita phalloides) and the destroying angel (Amanita virosa). It is one of the most potent and deadly toxins known to affect humans.

Phalloidine is a cyclic peptide that inhibits the function of actin, a protein involved in cell movement and division. By interfering with actin's normal functioning, phalloidine causes severe damage to the liver, kidneys, and other organs, leading to symptoms such as vomiting, diarrhea, dehydration, electrolyte imbalances, and potentially fatal organ failure.

It is important to note that phalloidine poisoning can be difficult to diagnose and treat, and it often requires prompt medical attention and supportive care to manage the symptoms and prevent long-term damage or death.

Troponin I is a protein that is found in the cardiac muscle cells (myocytes) of the heart. It is a component of the troponin complex, which also includes troponin C and troponin T, that regulates the calcium-mediated interaction between actin and myosin filaments during muscle contraction.

Troponin I is specific to the cardiac muscle tissue, making it a useful biomarker for detecting damage to the heart muscle. When there is injury or damage to the heart muscle cells, such as during a heart attack (myocardial infarction), troponin I is released into the bloodstream.

Measurement of cardiac troponin I levels in the blood is used in the diagnosis and management of acute coronary syndrome (ACS) and other conditions that cause damage to the heart muscle. Elevated levels of troponin I in the blood are indicative of myocardial injury, and the degree of elevation can help determine the severity of the injury.

Nonmuscle Myosin Type IIB (NMMIIB) is a type of motor protein that belongs to the myosin superfamily. It is involved in various cellular processes, including cell division, adhesion, migration, and maintenance of cell shape. NMMIIB is composed of two heavy chains, two regulatory light chains, and two essential light chains. The heavy chains have a motor domain that enables the protein to move along actin filaments, generating force and movement.

NMMIIB is widely expressed in non-muscle tissues, and its activity is regulated by phosphorylation and dephosphorylation of the regulatory light chains. Phosphorylation activates NMMIIB, leading to contractile forces that can alter cell shape and promote cell motility. In contrast, dephosphorylation inactivates NMMIIB, allowing for relaxation of the contractile forces.

Abnormal regulation of NMMIIB has been implicated in various pathological conditions, including cancer metastasis, cardiovascular diseases, and neurological disorders. Therefore, understanding the molecular mechanisms that regulate NMMIIB function is an important area of research with potential therapeutic implications.

Microfilament proteins are a type of structural protein that form part of the cytoskeleton in eukaryotic cells. They are made up of actin monomers, which polymerize to form long, thin filaments. These filaments are involved in various cellular processes such as muscle contraction, cell division, and cell motility. Microfilament proteins also interact with other cytoskeletal components like intermediate filaments and microtubules to maintain the overall shape and integrity of the cell. Additionally, they play a crucial role in the formation of cell-cell junctions and cell-matrix adhesions, which are essential for tissue structure and function.

Cell polarity refers to the asymmetric distribution of membrane components, cytoskeleton, and organelles in a cell. This asymmetry is crucial for various cellular functions such as directed transport, cell division, and signal transduction. The plasma membrane of polarized cells exhibits distinct domains with unique protein and lipid compositions that define apical, basal, and lateral surfaces of the cell.

In epithelial cells, for example, the apical surface faces the lumen or external environment, while the basolateral surface interacts with other cells or the extracellular matrix. The establishment and maintenance of cell polarity are regulated by various factors including protein complexes, lipids, and small GTPases. Loss of cell polarity has been implicated in several diseases, including cancer and neurological disorders.

Troponin C is a subunit of the troponin complex, which is a protein complex that plays a crucial role in muscle contraction. In the heart, the troponin complex is found in the myofibrils of cardiac muscle cells (cardiomyocytes). It is composed of three subunits: troponin C, troponin T, and troponin I.

Troponin C has the ability to bind calcium ions (Ca²+), which is essential for muscle contraction. When Ca²+ binds to troponin C, it causes a conformational change that leads to the exposure of binding sites on troponin I for another protein called actin. This interaction allows for the cross-bridge formation between actin and myosin, generating the force needed for muscle contraction.

In clinical settings, cardiac troponins (including troponin T and troponin I) are commonly measured in blood tests to diagnose and monitor heart damage, particularly in conditions like myocardial infarction (heart attack). However, Troponin C is not typically used as a biomarker for heart injury because it is less specific to the heart than troponin T and troponin I. Increased levels of Troponin C in the blood can be found in various conditions involving muscle damage or disease, making it less useful for diagnosing heart-specific issues.

Smooth muscle, also known as involuntary muscle, is a type of muscle that is controlled by the autonomic nervous system and functions without conscious effort. These muscles are found in the walls of hollow organs such as the stomach, intestines, bladder, and blood vessels, as well as in the eyes, skin, and other areas of the body.

Smooth muscle fibers are shorter and narrower than skeletal muscle fibers and do not have striations or sarcomeres, which give skeletal muscle its striped appearance. Smooth muscle is controlled by the autonomic nervous system through the release of neurotransmitters such as acetylcholine and norepinephrine, which bind to receptors on the smooth muscle cells and cause them to contract or relax.

Smooth muscle plays an important role in many physiological processes, including digestion, circulation, respiration, and elimination. It can also contribute to various medical conditions, such as hypertension, gastrointestinal disorders, and genitourinary dysfunction, when it becomes overactive or underactive.

Myosin-Light-Chain Kinase (MLCK) is an enzyme that plays a crucial role in muscle contraction. It phosphorylates the regulatory light chains of myosin, a protein involved in muscle contraction, leading to the activation of myosin and the initiation of the contractile process. MLCK is activated by calcium ions and calmodulin, and its activity is essential for various cellular processes, including cytokinesis, cell motility, and maintenance of cell shape. In addition to its role in muscle contraction, MLCK has been implicated in several pathological conditions, such as hypertension, atherosclerosis, and cancer.

Contractile proteins are a type of protein found in muscle cells that are responsible for the ability of the muscle to contract and generate force. The two main types of contractile proteins are actin and myosin, which are arranged in sarcomeres, the functional units of muscle fibers. When stimulated by a nerve impulse, actin and myosin filaments slide past each other, causing the muscle to shorten and generate force. This process is known as excitation-contraction coupling. Other proteins, such as tropomyosin and troponin, regulate the interaction between actin and myosin and control muscle contraction.

Time-lapse imaging is a medical imaging technique where images are captured at regular intervals over a period of time and then played back at a faster rate to show the progression or changes that occur during that time frame. This technique is often used in various fields of medicine, including microbiology, pathology, and reproductive medicine. In microbiology, for example, time-lapse imaging can be used to observe bacterial growth or the movement of individual cells. In pathology, it might help track the development of a lesion or the response of a tumor to treatment. In reproductive medicine, time-lapse imaging is commonly employed in embryo culture during in vitro fertilization (IVF) procedures to assess the development and quality of embryos before implantation.

Gastrulation is a fundamental process in embryonic development, characterized by the transformation of a initially flat layer of cells called the blastula into a three-layered structure known as the gastrula. This complex series of cellular movements and rearrangements establishes the foundation for the formation of the three primary germ layers: the ectoderm, mesoderm, and endoderm. These germ layers further differentiate to give rise to all the diverse cell types and tissues in the developing organism, including the nervous system, muscles, bones, and internal organs.

The precise mechanisms of gastrulation vary among different animal groups; however, common features include:

1. Formation of a blastopore: A small indentation or opening that forms on the surface of the blastula, which eventually develops into the primitive gut or anus in the gastrula.
2. Invagination: The process by which cells at the blastopore fold inward and migrate towards the interior of the embryo, forming the endodermal layer.
3. Epiboly: A coordinated movement of cells that spreads over and encloses the yolk within the embryo, contributing to the formation of the ectodermal layer.
4. Delamination: The separation and migration of cells from the epiblast (the outer layer of the blastula) to form the mesodermal layer in between the ectoderm and endoderm.

Gastrulation is a critical period in embryonic development, as errors during this process can lead to severe congenital abnormalities or even embryonic lethality. A thorough understanding of gastrulation has important implications for regenerative medicine, stem cell research, and the study of evolutionary developmental biology (Evo-Devo).

Protein binding, in the context of medical and biological sciences, refers to the interaction between a protein and another molecule (known as the ligand) that results in a stable complex. This process is often reversible and can be influenced by various factors such as pH, temperature, and concentration of the involved molecules.

In clinical chemistry, protein binding is particularly important when it comes to drugs, as many of them bind to proteins (especially albumin) in the bloodstream. The degree of protein binding can affect a drug's distribution, metabolism, and excretion, which in turn influence its therapeutic effectiveness and potential side effects.

Protein-bound drugs may be less available for interaction with their target tissues, as only the unbound or "free" fraction of the drug is active. Therefore, understanding protein binding can help optimize dosing regimens and minimize adverse reactions.

Skeletal muscle, also known as striated or voluntary muscle, is a type of muscle that is attached to bones by tendons or aponeuroses and functions to produce movements and support the posture of the body. It is composed of long, multinucleated fibers that are arranged in parallel bundles and are characterized by alternating light and dark bands, giving them a striped appearance under a microscope. Skeletal muscle is under voluntary control, meaning that it is consciously activated through signals from the nervous system. It is responsible for activities such as walking, running, jumping, and lifting objects.

The psoas muscles are a pair of muscles that are located in the lower lumbar region of the spine and run through the pelvis to attach to the femur (thigh bone). They are deep muscles, meaning they are located close to the body's core, and are surrounded by other muscles, bones, and organs.

The psoas muscles are composed of two separate muscles: the psoas major and the psoas minor. The psoas major is the larger of the two muscles and originates from the lumbar vertebrae (T12 to L5) and runs through the pelvis to attach to the lesser trochanter of the femur. The psoas minor, which is smaller and tends to be absent in some people, originates from the lower thoracic vertebrae (T12) and upper lumbar vertebrae (L1-L3) and runs down to attach to the iliac fascia and the pectineal line of the pubis.

The primary function of the psoas muscles is to flex the hip joint, which means they help to bring the knee towards the chest. They also play a role in stabilizing the lumbar spine and pelvis during movement. Tightness or weakness in the psoas muscles can contribute to lower back pain, postural issues, and difficulty with mobility and stability.

Biological models, also known as physiological models or organismal models, are simplified representations of biological systems, processes, or mechanisms that are used to understand and explain the underlying principles and relationships. These models can be theoretical (conceptual or mathematical) or physical (such as anatomical models, cell cultures, or animal models). They are widely used in biomedical research to study various phenomena, including disease pathophysiology, drug action, and therapeutic interventions.

Examples of biological models include:

1. Mathematical models: These use mathematical equations and formulas to describe complex biological systems or processes, such as population dynamics, metabolic pathways, or gene regulation networks. They can help predict the behavior of these systems under different conditions and test hypotheses about their underlying mechanisms.
2. Cell cultures: These are collections of cells grown in a controlled environment, typically in a laboratory dish or flask. They can be used to study cellular processes, such as signal transduction, gene expression, or metabolism, and to test the effects of drugs or other treatments on these processes.
3. Animal models: These are living organisms, usually vertebrates like mice, rats, or non-human primates, that are used to study various aspects of human biology and disease. They can provide valuable insights into the pathophysiology of diseases, the mechanisms of drug action, and the safety and efficacy of new therapies.
4. Anatomical models: These are physical representations of biological structures or systems, such as plastic models of organs or tissues, that can be used for educational purposes or to plan surgical procedures. They can also serve as a basis for developing more sophisticated models, such as computer simulations or 3D-printed replicas.

Overall, biological models play a crucial role in advancing our understanding of biology and medicine, helping to identify new targets for therapeutic intervention, develop novel drugs and treatments, and improve human health.

Diacetyl is a volatile, yellow-green liquid that is a byproduct of fermentation and is used as a butter flavoring in foods. The chemical formula for diacetyl is CH3COCH3. It has a buttery or creamy taste and is often added to microwave popcorn, margarine, and other processed foods to give them a buttery flavor.

Diacetyl can also be found in some alcoholic beverages, such as beer and wine, where it is produced naturally during fermentation. In high concentrations, diacetyl can have a strong, unpleasant odor and taste.

There has been concern about the potential health effects of diacetyl, particularly for workers in factories that manufacture artificial butter flavorings. Some studies have suggested that exposure to diacetyl may increase the risk of developing lung disease, including bronchiolitis obliterans, a serious and sometimes fatal condition characterized by scarring and narrowing of the airways in the lungs. However, more research is needed to fully understand the health effects of diacetyl and to determine safe levels of exposure.

I'm sorry for any confusion, but "Punicaceae" is not a recognized term in modern medicine or medical botany. It is possible that you may be referring to "Punica granatum," which is the scientific name for the pomegranate tree and its fruit. The pomegranate has been studied for its potential medicinal properties, including anti-inflammatory, antioxidant, and anticancer effects. However, I would need more context to provide a more specific definition or explanation.

"Physarum" is not a term that has a specific medical definition. It is a genus of slime molds, which are single-celled organisms that can behave as multicellular entities under certain conditions. They are often studied in biological research for their unique behaviors and abilities, but they do not have direct relevance to human medicine.

Isometric contraction is a type of muscle activation where the muscle contracts without any change in the length of the muscle or movement at the joint. This occurs when the force generated by the muscle matches the external force opposing it, resulting in a balanced state with no visible movement. It is commonly experienced during activities such as holding a heavy object in static position or trying to push against an immovable object. Isometric contractions are important in maintaining posture and providing stability to joints.

It is composed of actin and myosin II bundles, thus the term actomyosin. The actomyosin ring operates in contractile motion, ... Bi, E.; Maddox, P.; Lew, D. J.; Salmon, E. D.; McMillan, J. N.; Yeh, E.; Pringle, J. R. (1998). "Involvement of an actomyosin ... In plant cells, there is no actomyosin ring. Instead, a cell plate grows centrifugally outwards from the center of the plane of ... Apart from cytokinesis, in which the ring constricts as the cells divide (Figure 2), actomyosin ring constriction has also been ...
It also inhibits skeletal muscle actomyosin MgATPase activity and calcium activated force generation by actomyosin in the ... Goodno, C.C.; Taylor, E.W. (1982). "Inhibition of actomyosin ATPase by vanadate". Proceedings of the National Academy of ...
Kumar, Abhishek; Maitra, Ananyo; Sumit, Madhuresh; Ramaswamy, Sriram; Shivashankar, G. V. (21 January 2014). "Actomyosin ...
Moos C, Feng IN (Oct 1980). "Effect of C-protein on actomyosin ATPase". Biochimica et Biophysica Acta (BBA) - General Subjects ...
Moos C, Feng IN (October 1980). "Effect of C-protein on actomyosin ATPase". Biochimica et Biophysica Acta (BBA) - General ...
In the process, she co-discovered actomyosin. In order to get myosin to analyze, Banga extracted it from rabbit muscles - she ... Ilona Banga (1906-1998) was a Hungarian biochemist known for co-discovering actomyosin and working to characterize how actin ... describe their groundbreaking experiments leading to the discovery of actomyosin I Studies from the Institute of Medical ...
ROCK kinases induce actomyosin-based contractility and phosphorylate TAU and MAP2 involved in regulating myosins and other ... RhoA is prevalent in regulating cell shape, polarity and locomotion via actin polymerization, actomyosin contractility, cell ... Cytokinesis is defined by actomyosin-based contraction. RhoA-dependent diaphanous-related formins (DRFs) localize to the ... mostly actin stress fibers formation and actomyosin contractility. It acts upon several effectors. Among them, ROCK1 (Rho- ...
subscription required) Cantelli, Gaia (2016). Transcriptional programs controlling actomyosin contractility in melanoma. ethos. ...
By the end of the 1940s Szent-Györgyi's team had postulated with evidence that contraction of actomyosin was equivalent to ... However, in one of his last contributions to muscle research, Szent-Györgyi demonstrated that actomyosin driven by ATP was the ... Cross-bridge theory states that actin and myosin form a protein complex (classically called actomyosin) by attachment of myosin ... Szent-Györgyi, A (1949). "Free-energy relations and contraction of actomyosin". The Biological Bulletin. 96 (2): 140-161. doi: ...
Siemankowski RF, Wiseman MO, White HD (February 1985). "ADP dissociation from actomyosin subfragment 1 is sufficiently slow to ... Lymn RW, Taylor EW (December 1971). "Mechanism of adenosine triphosphate hydrolysis by actomyosin". Biochemistry. 10 (25): 4617 ... "Kinetics of nucleoside triphosphate cleavage and phosphate release steps by associated rabbit skeletal actomyosin, measured ...
In the actomyosin ATPase cycle, the hydrolysis of ATP by enzymes leads to the generation of force and motion. Taylor also has ... The actomyosin ATP hydrolysis cycle in muscle motility was intended to show a direct correlation in the regulation of ATP ... He found the dissociation of phosphate in the actomyosin mechanism to be a slow rate-limiting step, while this step occurred ... Aware that ATP was hydrolyzed in the polymerization of actin, Taylor was confused on whether it dissociated actomyosin through ...
Korn, ED (1978). "Biochemistry of actomyosin-dependent cell motility (a review)". Proceedings of the National Academy of ...
TnI inhibits ATP-ase activity of acto-myosin; TnC is a Ca2+-binding subunit, playing the main role in Ca2+ dependent regulation ...
Inhibition of actomyosin MgATPase and regulation by phosphorylation". J. Biol. Chem. 265 (17): 10148-55. doi:10.1016/S0021-9258 ...
The source of cytoskeletal traction is actomyosin contractility. Increased external stiffness leads to a signal transduction ... actomyosin contractility, and cytoskeletal organization. As a result, these changes can cause a cell to rearrange its ...
Inhibition of actomyosin MgATPase and regulation by phosphorylation". The Journal of Biological Chemistry. 265 (17): 10148-55. ...
"Myosin cleft movement and its coupling to actomyosin dissociation". Nature Structural & Molecular Biology. 10 (10): 831-835. ...
Wolfenson H, Bershadsky A, Henis YI, Geiger B (May 2011). "Actomyosin-generated tension controls the molecular kinetics of ...
Due to its importance in mitosis, the molecular components and dynamics of the mitotic actomyosin cortex is an area of active ... Matthews HK, Delabre U, Rohn JL, Guck J, Kunda P, Baum B (August 2012). "Changes in Ect2 localization couple actomyosin- ... Rounding forces are driven by reorganization of F-actin and myosin (actomyosin) into a contractile homogeneous cell cortex that ... Stewart MP, Helenius J, Toyoda Y, Ramanathan SP, Muller DJ, Hyman AA (January 2011). "Hydrostatic pressure and the actomyosin ...
The actomyosin cortex is attached to the cell membrane via membrane-anchoring proteins called ERM proteins that plays a central ... Rosa, A (2015). "Ect2/Pbl acts via Rho and polarity proteins to direct the assembly of an isotropic actomyosin cortex upon ... The cell cortex, also known as the actin cortex, cortical cytoskeleton or actomyosin cortex, is a specialized layer of ... Stewart MP, Helenius J, Toyoda Y, Ramanathan SP, Muller DJ, Hyman AA (January 2011). "Hydrostatic pressure and the actomyosin ...
Yu, L.C.; Brenner, B. (March 1989). "Structures of actomyosin crossbridges in relaxed and rigor muscle fibers". Biophysical ...
These actomyosin rings invaginate to separate all nuclei for one another in the syncytial blastoderm. Anillin has a unique ... Goldbach P, Wong R, Beise N, Sarpal R, Trimble WS, Brill JA (May 2010). "Stabilization of the actomyosin ring enables ... Anillins are also enriched at other actomyosin rings, most significantly, those at the leading edge of the Drosophila embryo ... Anillins have also been shown to organize the actomyosin cytoskeleton into syncytial structures observed in Drosophila embryos ...
The actomyosin filaments of β-cells contract and release insulin. Secretion of insulin in large amounts decreases the ...
... is a major downstream effector of the small GTPase RhoA and is a regulator of the actomyosin cytoskeleton which promotes ... In humans, the main function of ROCK1 is actomyosin contractility. As mentioned before, this contributes to many proximal ...
Stewart MP, Helenius J, Toyoda Y, Ramanathan SP, Muller DJ, Hyman AA (January 2011). "Hydrostatic pressure and the actomyosin ... actomyosin assemblies (F-actin, myosin motors, and associated binding, nucleating, capping, stabilizing, and crosslinking ...
Apart from actomyosin-related genes, several disease genes have recently been implicated in mitotic cell rounding. These ... "ETH ETH E-Collection: The Mechanism of Mitotic Rounding: Role of the Actomyosin Cortex - ETH". e-collection.library.ethz.ch. ... Sorce, B (2015). "Mitotic cells contract actomyosin cortex and generate pressure to round against or escape epithelial ... "Changes in Ect2 localization couple actomyosin-dependent cell shape changes to mitotic progression". Developmental Cell. 23 (2 ...
Like in Xenopus, actomyosin contractility plays a major role in constricting the apical side of the cell. The constricting ... In these cells, apical constriction occurs when actomyosin contractility folds the cell membrane to reduce the apical surface ... Lee, J.; Harland, R. M. (2007). "Actomyosin contractility and microtubules drive apical constriction in Xenopus bottle cells". ...
Deutsch A, Nilsson R (1954). "On the dephosphorylation and deamination of adenosine triphosphate by actomyosin gel". Acta Chem ...
"Plakophilin 2 couples actomyosin remodeling to desmosomal plaque assembly via RhoA". Molecular Biology of the Cell. 21 (16): ...
Actomyosin-based cortical flows direct a reorganization of the plasma membrane and cell cortex of the neuroblast, which is ... Oon, Chet Huan; Prehoda, Kenneth E (2021-11-15). "Phases of cortical actomyosin dynamics coupled to the neuroblast polarity ...
It is composed of actin and myosin II bundles, thus the term actomyosin. The actomyosin ring operates in contractile motion, ... Bi, E.; Maddox, P.; Lew, D. J.; Salmon, E. D.; McMillan, J. N.; Yeh, E.; Pringle, J. R. (1998). "Involvement of an actomyosin ... In plant cells, there is no actomyosin ring. Instead, a cell plate grows centrifugally outwards from the center of the plane of ... Apart from cytokinesis, in which the ring constricts as the cells divide (Figure 2), actomyosin ring constriction has also been ...
Natural actomyosin at µ = 0.6 appears in various forms, including the regular arrowhead structures originally reported by ... ELECTRON MICROSCOPIC INVESTIGATIONS OF ACTOMYOSIN AS A FUNCTION OF IONIC STRENGTH N. Ikemoto, N. Ikemoto ... Natural actomyosin at µ = 0.6 appears in various forms, including the regular arrowhead structures originally reported by ... N. Ikemoto, S. Kitagawa, A. Nakamura, J. Gergely; ELECTRON MICROSCOPIC INVESTIGATIONS OF ACTOMYOSIN AS A FUNCTION OF IONIC ...
2003). Actomyosin motility on nanostructured resist polymers and silanes. . * Sundberg, M., Balaz, M., Bunk, R., Rosengren- ... 2004). Nanotechnology, surface science and actomyosin motility in vitro. . * Rosengren-Holmberg, J., Karlsson, J.G., Nicholls, ... 2003). Actomyosin motility on nanostructured surfaces. Biochemical and Biophysical Research Communications. 301. 783-788. ... 2006). Selective spatial localization of actomyosin motor function by chemical surface patterning. Langmuir. 22 (17). 7302-7312 ...
ICAM-1 signals to an actomyosin network at the base of canalicular microvilli, thereby controlling the dynamics and size of ... Indeed, EBP50 expression is required for ICAM-1-mediated control of BC morphogenesis and actomyosin. Our findings indicate that ... ICAM-1 nanoclusters regulate hepatic epithelial cell polarity by leukocyte adhesion-independent control of apical actomyosin ...
A Combination of Actin Treadmilling and Cross-Linking Drives Contraction of Random Actomyosin Arrays.. Oelz DB, Rubinstein BY, ...
15. Imaging and Nanomanipulation of an Actomyosin Motor. S. Nishikawa, T. Komori, T. Ariga, T. Okada, M. Morimatsu, Y. Ishii, ...
Actomyosin contractility drives bile regurgitation as an early response during obstructive cholestasis ... The apical cortex is also rich in actomyosin, in particular near the junctions, serving as a mechanical contractile element in ...
the glomerular basement membrane, actomyosin, and fibroblast surface antigens in normal, diseased, and transplanted human ...
Actomyosin dynamics drive local membrane component organization in an in vitro active composite layer.. Proc Natl Acad Sci U S ...
cytokinesis, actomyosin contractile ring assembly [IMP. ] cytokinesis [IGI. ][IMP. ] Molecular Function:. microfilament motor ... Type II myosin heavy chain, required for wild-type cytokinesis and cell separation; localizes to the actomyosin ring; binds to ...
Wiggan O, Shaw AE, DeLuca JG, Bamburg JR: ADF/cofilin regulates actomyosin assembly through competitive inhibition of myosin II ...
The regulation of actomyosin by Ca2+ binding to troponin C can be expressed as an increase in the stability of strongly bound ... In the actomyosin system, cooperativity between adjacent tropomyosin molecules plays a significant role in enhancing the degree ... For comparison, it is instructive to look at the system for regulation of the actomyosin contractile system in skeletal muscle ... Pathway of the microtubule-dynein ATPase and the structure of dynein: A comparison with actomyosin. A ...
The intracellular actin cytoskeleton and nucleus were found to be elongated and aligned in an actomyosin tension-dependent ...
Functional studies have shown that the mutant βMHC protein has impaired acto-myosin interaction and that expression of the ...
... changes in actomyosin structure and infiltration of adipocytes into muscle fibers 22. Clark BC, Manini TM. Functional ...
Alix-mediated assembly of the actomyosin-tight junction polarity complex preserves epithelial polarity and epithelial barrier. ...
James Bear) Title: "A photopolymer-based hydrogel system reveals distinct actomyosin-based mechano-responses in fibroblast ...
The contractile forces generated by the actomyosin ring help overcome the resistance of the plasma membrane, enabling the ...
... and nuclear positioning of cells in the Drosophila wing imaginal disc are defined by the concurrent patterning of actomyosin ... chaperone-assisted assembly of the actomyosin cytoskeleton is also discussed. ...
Tn consists of three components:Tn-I which is the inhibitor of actomyosin ATPase, Tn-T which contains the binding site for ...
Elongator controls cortical interneuron migration by regulating actomyosin dynamics. Cell Research. doi:10.1038/cr.2016.112 ... Elongator controls cortical interneuron migration by regulating actomyosin dynamics [Poster presentation]. ISDN, France. ...
beta-actin/Bap47; l(1)G0177; cellular cytoskeletal beta-actin; l(1)G0079; actomyosin; ACT5C; actin 5C; NON-CANONICAL BRAHMA ... beta-actin/Bap47; l(1)G0177; cellular cytoskeletal beta-actin; l(1)G0079; actomyosin; ACT5C; actin 5C; NON-CANONICAL BRAHMA ... synonym, label: actomyosin, type: }, pub: { core: { symbol: , iri: http://flybase.org/reports/Unattributed ...
Actomyosin Subfragments*Actomyosin Subfragments. *Subfragments, Actomyosin. Heavy Meromyosin Subfragment-1*Heavy Meromyosin ...
ROCK and the actomyosin network control biomineral growth and morphology during sea urchin skeletogenesis. Hijaze, E., Gildor, ...
... and actomyosin ATPase variability among fibers was ~60% lower. In contrast, only actomyosin ATPase activity of type IIb fibers ... and actomyosin ATPase variability among fibers was ~60% lower. In contrast, only actomyosin ATPase activity of type IIb fibers ... and actomyosin ATPase variability among fibers was ~60% lower. In contrast, only actomyosin ATPase activity of type IIb fibers ... and actomyosin ATPase variability among fibers was ~60% lower. In contrast, only actomyosin ATPase activity of type IIb fibers ...
This was accompanied by 1) a higher ATP demand of myosin heads in the disordered-relaxed conformation; 2) faster actomyosin ... mutations impact myosin presence/functionality in human adult mature myofibers by disrupting the ATPase activity and actomyosin ...
Actomyosin II interaction modulates cell cortex stability. In Cell Biol Int, volume 29, 2005. [bibtex] [pdf]. ...
Actomyosin-Driven Division of a Synthetic Cell. Lucia Baldauf, Lennard van Buren, Federico Fanalista, and Gijsje Hendrika ... In animal cells deformation is done by actomyosin networks. These networks are composed mainly of two complex molecules, a ...
Vinculin controls talin engagement with the actomyosin machinery. Nat Commun 6, 10038 (2015). ...
Plays a key role in tissue tension and 3D tissue shape by regulating cortical actomyosin network formation. Acts via ARHGAP18, ...
  • It is composed of actin and myosin II bundles, thus the term actomyosin. (wikipedia.org)
  • Rho-kinases such as ROCK1 has been found to regulate actomyosin contraction through phosphorylation of the myosin light chain (MLC). (wikipedia.org)
  • The actin cytoskeleton consists of polymerized actin filaments (F-actin), which serve as a scaffold for non-muscle myosin II to form the actomyosin contractile system. (frontiersin.org)
  • The cellular machinery that controls INM involves a protein complex of actin and myosin, called actomyosin, as well as microtubule-dependent systems," notes Dr. Wang. (sciencedaily.com)
  • Since the actomyosin network regulates cell mechanics, we speculated that mechanosignaling could be impaired when VANGL2 is disrupted. (frontiersin.org)
  • ALKBH4-dependent demethylation of actin regulates actomyosin dynamics. (nih.gov)
  • A Combination of Actin Treadmilling and Cross-Linking Drives Contraction of Random Actomyosin Arrays. (stowers.org)
  • Furthermore, activation of RhoA signaling restored actomyosin organization in Vangl2 Lp/+ , confirming RhoA as an effector of VANGL2. (frontiersin.org)
  • Actomyosin dynamics drive local membrane component organization in an in vitro active composite layer. (ncbs.res.in)
  • Isotropic actomyosin dynamics promote organization of the apical cell cortex in epithelial cells. (ptglab.com)
  • In molecular biology, an actomyosin contractile ring is a prominent structure during cytokinesis. (wikipedia.org)
  • Apart from cytokinesis, in which the ring constricts as the cells divide (Figure 2), actomyosin ring constriction has also been found to activate during wound closure. (wikipedia.org)
  • These structures are not made out of actomyosin, but serve a similar role in constricting and permitting cytokinesis. (wikipedia.org)
  • The Vangl2 Lp mutation causes lung branching defects due to dysfunctional actomyosin-driven morphogenesis. (frontiersin.org)
  • The actomyosin ring operates in contractile motion, although the mechanism on how or what triggers the constriction is still an evolving topic. (wikipedia.org)
  • Natural actomyosin at µ = 0.6 appears in various forms, including the regular arrowhead structures originally reported by Huxley (1), when it has been stained negatively with 1% uranyl acetate. (rupress.org)
  • We further show that this increased cell density is not due to differences in proliferation, but rather actomyosin-dependent changes in the multicellular architecture of aggregates. (elifesciences.org)
  • Vangl2 Lp/+ tracheal epithelial cells (TECs) and alveolar epithelial cells (AECs) exhibited highly disrupted actomyosin networks and focal adhesions (FAs). (frontiersin.org)
  • Physiological evidence of an increase in actomyosin-based contractility following CalyA treatment was demonstrated in experiments in which cells generated tears in their cell centers in response to the drug. (nih.gov)
  • 6. Effects of substrate stiffness and actomyosin contractility on coupling between force transmission and vinculin-paxillin recruitment at single focal adhesions. (nih.gov)
  • During Drosophila gastrulation, actomyosin contractility drives apical constriction in ventral cells, leading to furrow formation and mesoderm invagination. (ibecbarcelona.eu)
  • Since his groundbreaking discovery of the first unconventional non-filamentous myosin, myosin I, in the single-cell soil protozoan Acanthamoeba castellanii , Dr. Korn's research has focused on the function and regulation of the actomyosin system. (nih.gov)
  • Understanding the molecular-mechanical regulation of the actomyosin cortex of cancer cells and the solid tumor microenvironment (primary and metastatic) for deciphering self-organization in cancer biology. (nih.gov)
  • Previous studies have suggested that the actin-based centripetal flow process in sea urchin coelomocytes is the result of a two-part mechanism, actin polymerization at the cell edge coupled with actomyosin contraction at the cell center. (nih.gov)
  • In the present study, we have extended the testing of this two-part model by attempting to stimulate actomyosin contraction via treatment of coelomocytes with the phosphatase inhibitor Calyculin A (CalyA). (nih.gov)
  • Previously we demonstrated a pulsatile actomyosin contraction in epithelial basal surface to induce the underlying tissue elongation during Drosophila ovary development. (ens-lyon.fr)
  • Inhibiting contraction of actomyosin, a structure of actin and myosin, reduced pressure inside cells and caused a switch from lobopodial to lamellipodial movement. (nih.gov)
  • I think this was not, I think, looking at it from the present point of view, not really an ideal project because the properties that are important for muscle contraction have to do with organized fibers of actomyosin, and by the time you have it in solution, it's probably been dispersed too far. (nih.gov)
  • Actin-based centripetal flow: phosphatase inhibition by calyculin-A alters flow pattern, actin organization, and actomyosin distribution. (nih.gov)
  • In addition, the structure and dynamics of the cell center are transformed due to the accumulation of actin and membrane in this region and the constriction of the central actomyosin ring. (nih.gov)
  • Regionalized tissue fluidization by an actomyosin cable is required for epithelial gap closure during insect gastrulation. (janelia.org)
  • Since this developmental solution utilized during epiboly resembles the mechanism of wound healing in other systems, we propose actomyosin cable-driven local tissue fluidization as a conserved morphogenetic module for closure of epithelial gaps. (janelia.org)
  • Septins provide microenvironment sensing and cortical actomyosin partitioning in motile amoeboid T lymphocytes. (nih.gov)
  • de Toulouse <br />When : Thursday 28th May at 11 am <br />Where : Salle CO23 (grande salle de réunions du CBP rez-de-chaussée LR6) <br />Title : Controlling mechanism of basal actomyosin oscillation during Drosophila ovary development <br />In epithelia, individual cell is split into apical and basolateral regions. (ens-lyon.fr)
  • Western blotting and immunofluorescent localization with antibodies against the phosphorylated form of the myosin regulatory light chain (MRLC) suggested that the demonstrated constriction of actomyosin distribution was the result of CalyA-induced phosphorylation of MRLC. (nih.gov)
  • Here, we firstly explored the controlling mechanism of basal actomyosin oscillation. (ens-lyon.fr)
  • 7. Vinculin controls talin engagement with the actomyosin machinery. (nih.gov)
  • Our results suggest that fluidization of the leading edge is effected by a heterogeneous actomyosin cable that drives sequential eviction and intercalation of individual cells away from the serosa margin. (janelia.org)
  • The team thus hypothesized that the tight-fitting nucleus might be pulled forward like a piston by actomyosin contractions to pressurize the front of the cell and form lobopodia. (nih.gov)