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 ?
The distance a single myosin can move during the hydrolysis of a single ATP molecule is limited to half the helical pitch of the actin filaments, as described above.
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.
Rac, Rho and Cdc42 are the three best-characterized members of the Rho family (Etienne-Manneville and Hall, 2002), which can interact with and activate downstream effectors to control the assembly of actin filaments and their organization into complex structures (Bishop and Hall, 2000).
Cell nuclei and actin filaments were stained according to the methods of Yoon et al.
They found that SS2 caused actin filaments to clump together--or bundle--which stopped plant cells from dividing.
Thickening of the actin filaments at the cell edge provided the bending force to extrude the virus particles.
Actin filaments are fine threads composed of multiple subunits--polymers that line up like a string of pop beads--which give structure to the cell, as well as drive shape changes, cell movements, and other cellular processes.
Using actin-specific rhodamine phalloidin as a fluorescent marker, 5-HT-treated cells were found to have fewer actin filaments at the cell periphery, increased stress fiber formation, and smoother, denser edges than control cells.
It also disrupts the actin filaments around the hair follicle which appear to exert a constraining force similar to that of a muscle fiber, Dr.
Additionally, living isolated pharynxes were treated with dihydrocytochalasin B, a compound known to disrupt actin filaments.
Abstract #2128: Vasodilator-Stimulated Phosphoprotein (VASP) Promotes Arp2/3 Complex Mediated Actin Polymerization, Prevents Branching and Stabilizes Actin Filaments (Session 416, Actin Dynamics and Assembly III) 2.