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 ?
Actin was generally distributed with circumferential banding near the edge of the cell and a cytoplasmic meshwork was becoming apparent in certain cells (Fig.
5 cm) carcinoma Reference Cell Markers EM Metastasis Current Actin (+) T, M No case Keratin (+) S100 (-) GFAP (+) 4 Actin (+) M No Keratin (-) S100 (+) 5 Actin (+) NA No Keratin (-) S100 (+) 2 Actin (+/+) T, D Yes Keratin (+/-) S100 (+/-) 3 NA NA Yes 7 Actin (+) T, D Yes Keratin (+) S100 (+) * LM indicates light microscopy; EM, electron microscopy; GFAP, glial fibrillary acidic protein; T, tonofilaments; M, myofilaments; NA, not available; and D, desmosomes.
Scientists had already linked HCM and DCM to 14 actin gene abnormalities.
It's truly pioneering stuff," comments Alexander Mogilner of the University of California, Davis who has performed research on the self-organization of actin and myosin.
Actin participates in many protein-protein interactions, including self-association of actin to form F-actin.
We propose a tentative model of cartilage damage by Fn-fs: after Fn-fs bind to receptor, receptor aggregation is disrupted and actin distribution is altered.
Shigella requires actin to rocket around the host cell before punching into an adjacent cell, said the Pasteur researchers, who made their discovery in human cells grown in culture in the laboratory.
To create the three-dimensional structures needed for BD simulations, the Homology module of the Insight[R]II modeling package (Accelrys, San Diego, CA) was used to build the tertiary structures of fish aldolase and actin.
13,14) Immunohistochemistry alone is not sufficient to allow for an exact categorization of a particular cell as a myofibroblast because these cells display an immunophenotypic heterogeneity that is, a variable positivity for vimentin, alpha smooth-muscle actin, desmin, and heavy-chain smooth-muscle myosin.
On the other hand, the levels of actin were not changed by exposure to chrysotile, crocidolite, or Cd[Cl.
The most striking change in the cellular structure of the host cell is the formation of characteristic actin pedestals.
Like vaccinia, the AIDS virus also exits without rupturing the host cell, says Theriot, who believes Way's work may prompt researchers to see if actin filaments play a role in AIDS virus release.