actin


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actin,

a protein abundantly present in many cells, especially muscle cells, that significantly contributes to the cell's structure and motility. Actin can very quickly assemble into long polymer rods called microfilaments. These microfilaments have a variety of roles—they form part of the cell's cytoskeleton, they interact with myosinmyosin
, one of the two major protein constituents responsible for contraction of muscle. In muscle cells myosin is arranged in long filaments called thick filaments that lie parallel to the microfilaments of actin.
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 to permit movement of the cell, and they pinch the cell into two during cell division. In muscle contraction, filaments of actin and myosin alternately unlink and chemically link in a sliding action. The energy for this reaction is supplied by adenosine triphosphateadenosine triphosphate
(ATP) , organic compound composed of adenine, the sugar ribose, and three phosphate groups. ATP serves as the major energy source within the cell to drive a number of biological processes such as photosynthesis, muscle contraction, and the synthesis of
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.

actin

[′ak·tən]
(biochemistry)
A muscle protein that is the chief constituent of the Z-band myofilaments of each sarcomere.
References in periodicals archive ?
2+]-dependent movement of troponin and tropomyosin on actin filament, (ii) the interaction site(s) with myosin, and lastly (iii) the structure of the tropomyosin junction, of which the formation is essential to bind to actin filaments.
Then, ATP is hydrolyzed to ADP and Pi, which sequentially dissociate from the myosin and cause the myosin to rebind to the actin at a new location and generate displacement (force) (state (3) in Fig.
Hepatocyte swelling leads to rapid decrease of the G-/total actin ratio and increases actin mRNA levels," FEBS Letters, vol.
The actin forms an architecture inside the nucleus and turns on the bone-making genetic program.
In the above-mentioned simulating model, when we slided actin filaments present on both sides of a myosin filament toward center of A band in a single sarcomere as it occurs during contraction, two Z discs on either side of A band moved toward center of the sarcomere, as shown in Figure 1.
He said that they have discovered that Plasmodium actin filaments are very different from other actin filaments and now that they know the structural basis for this, we can look for ways to specifically interfere with the parasite cytoskeleton to the of this protein in the parasite in high detail.
Actin is the major cytoskeletal protein and involved in a variety of processes including cellular motility, intracellular transport, cytoskeletal structure, cell-surface mobility, cytokinesis, cytoplasmic streaming, clot retardation, microvillar movement, exocytosis and endocytosis, and probably chromosomal condensation and mitosis (Sheterline et al.
Anillin contains an actin binding domain that is necessary for the protein's direct association with actin.
Tomato actin primers produced the expected ~240 base pair PCR product only in tomato for all sampling dates.
For healthy cells to move normally, these actin polymers push against a cell's membrane, protruding and propelling the cell in one direction or another.
In the lab, Blough and his colleagues used myosin -- a protein found in muscle that is responsible for generating the force of muscle contraction -- as the motor, and actin -- another protein isolated from muscle -- as the carrier.