actin

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actin

 [ak´tin]
a muscle protein localized in the I band of myofibrils; acting along with myosin particles, it is responsible for the contraction and relaxation of muscle fibers.

ac·tin

(ak'tin),
One of the protein components into which actomyosin can be split; it can exist in a fibrous form (F-actin) or a globular form (G-actin).

actin

/ac·tin/ (ak´tin) a muscle protein localized in the I band of the myofibrils; acting along with myosin, it is responsible for contraction and relaxation of muscle. It occurs in globular (G-actin) and fibrous (F-actin) forms.

actin

(ăk′tĭn)
n.
A protein that forms the microfilaments of the eukaryotic cytoskeleton and plays an important role in cell movement, shape, and internal organization. In muscle cells, it functions with myosin to produce contraction.

actin

a protein forming the thin filaments in muscle fibers that are pulled on by myosin cross-bridges to cause a muscle contraction. Some bacteria forms actin tails to use for motility. See also myosin.

Actin

One of two major muscle proteins—the other is myosin—which is an ATPase that binds to adenine nucleotides. In concert with myosin, actin is a filamentous protein responsible for muscle contraction, and has an active mechanicochemical role in cell function; it is divided into a 46-kD monomeric form, G-actin and a mature contractile form, F-actin, formed from G-actin polymers, capable of functioning in absence of myosin.

ac·tin

(ak'tin)
One of the protein components into which actomyosin can be split; it can exist in a fibrous form (F-actin) or a globular form (G-actin).

actin

A contractile protein in muscle, found in the thin filaments, to which the myosin cross-bridges bind. Actin filaments are also abundant inside all nucleated cells where they form the cytoskeleton, determining cell shape and, in the case of amoebic cells, cell movement. An actin contractile ring forms around the equator of a dividing cell at the end of MITOSIS and tightens so as to pinch the two daughter cells apart.

actin

a contractile protein found in the muscles of all animals from protozoa to vertebrates and in the MICROFILAMENTS of all cells. The energy for contraction is derived from ATP; See MYOSIN.
Figure 1: The autonomic nervous system. Actions on secretory functions (heart diagrams indicate release into the circulation). Sympathetic actions on the left and parasympathetic actions on the right. Solid arrows: stimulation (contraction or secretion); broken arrows: inhibition.

actin

globular protein molecule which readily links with others (with consumption of ATP) to form long, double-helical strands. Such actin filaments are found in a wide variety of animal and plant cells, as well as forming the structural core and main (but not only) component of the thin filaments in the myofibrils of all animal muscles. Actin is thus a protein of great evolutionary antiquity and vertebrate striated muscles are unusual only in having a very high content of it (80% of total protein), and in its highly ordered locations within the cells, where thin filaments alternate with thick filaments containing actin's partner protein myosin, to form the cross-striated pattern. See also muscle, muscle fibres; Figure 1.

actin (akˑ·tin),

n one of a pair of myofilaments involved in muscle contractions. See also myosin.

actin

a muscle protein localized in the I band of myofibrils; acting along with myosin particles, it is responsible for the contraction and relaxation of muscle.

actin F
assembly of actin G monomers into filaments.
actin filaments
smallest filamentous proteins involved in a static role in cell structure and a dynamic role in cell movement.
actin G
monomeric globular protein which assembles into actin filaments.
References in periodicals archive ?
Studies in budding yeast revealed that myosin and dynein are molecular motors that walk along microtubules or actin filaments and can contribute to spindle positioning directly by generating a pulling or pushing force (Huisman and Segal, 2005; Person and Bloom, 2004).
We found that treatment of MCF7 or MDA-MB-453 cells with actein altered their cell structures, since the actin filaments aggregated around the cell nuclei and the nuclei appeared donut-shaped (Fig.
The actin filaments that were parallel to the cell edge appeared to have thickened (Figures 7A and B compared to Figures 1A and 1B).
Cytochalasin B slows but does not prevent monomer addition at the barbed end of the actin filament.
These studies (29,30) suggest that actin filaments are regulated by receptor-mediated cAMP and [Ca.
Unipolar reorganization of F-actin layer at bacterial division and bundling of actin filaments by plastin correlate with movement of Shigella flexneri within HeLa cells.
Pollard has been one of the leaders in elucidating the mechanisms by which actin filaments form and dissociate, and the role which this process plays in cell movement.
Living cells maintain a high degree of functional and structural organization which largely depends on a highly dynamic scaffold, the cytoskeleton, with microtubules (MTs) and actin filaments as the central elements.
2+] sensitive, 41,000-dalton protein which reversibly blocks the "barbed" ends of actin filaments but does not sever them.
Gc binds actin released from cells upon injury, and the Gc-actin complexes are rapidly cleared from the circulation, thereby preventing the harmful effects of actin filaments in blood vessels.
They may be especially important to the cochlea's hair cells because the stereocilia owe their stiffness to bundles of actin filaments that are continuously broken apart and rebuilt.
Three work packages are defined: (i) the microscopic mechanism of the interaction of ABPs with actin filaments on the tread-milling behaviour of actin.